diff --git a/devtools/client/responsive.html/index.css b/devtools/client/responsive.html/index.css
index 63bccdac49..c0ed5330b3 100644
--- a/devtools/client/responsive.html/index.css
+++ b/devtools/client/responsive.html/index.css
@@ -78,7 +78,7 @@ html, body {
 }
 
 select {
-  -moz-appearance: none;
+  appearance: none;
   background-color: var(--theme-toolbar-background);
   background-image: var(--viewport-selection-arrow);
   background-position: 100% 50%;
diff --git a/devtools/client/themes/animationinspector.css b/devtools/client/themes/animationinspector.css
index 3b2567955f..1a23ed7497 100644
--- a/devtools/client/themes/animationinspector.css
+++ b/devtools/client/themes/animationinspector.css
@@ -188,7 +188,7 @@ body {
 }
 
 #timeline-rate select.devtools-button {
-  -moz-appearance: none;
+  appearance: none;
   text-align: center;
   font-family: inherit;
   color: var(--theme-body-color);
diff --git a/devtools/client/themes/commandline.inc.css b/devtools/client/themes/commandline.inc.css
index db78bedf3b..2703517821 100644
--- a/devtools/client/themes/commandline.inc.css
+++ b/devtools/client/themes/commandline.inc.css
@@ -34,7 +34,7 @@
 }
 
 #developer-toolbar {
-  -moz-appearance: none;
+  appearance: none;
   padding: 0;
   min-height: 32px;
   background-color: var(--gcli-background-color);
@@ -42,7 +42,7 @@
 }
 
 #developer-toolbar > toolbarbutton {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background-color: transparent;
   margin: 0;
@@ -122,7 +122,7 @@ html|*#gcli-output-frame {
 #gcli-tooltip {
   border-width: 0;
   background-color: transparent;
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .gclitoolbar-input-node,
@@ -140,7 +140,7 @@ html|*#gcli-output-frame {
 }
 
 .gclitoolbar-input-node {
-  -moz-appearance: none;
+  appearance: none;
   color: var(--gcli-input-color);
   background-color: var(--gcli-input-background);
   background-repeat: no-repeat;
diff --git a/devtools/client/themes/common.css b/devtools/client/themes/common.css
index 8b807d0dba..268add3db1 100644
--- a/devtools/client/themes/common.css
+++ b/devtools/client/themes/common.css
@@ -70,7 +70,7 @@ html|button, html|select {
 }
 
 .devtools-autocomplete-listbox {
-  -moz-appearance: none !important;
+  appearance: none !important;
   background-color: transparent;
   border-width: 0px !important;
   margin: 0;
@@ -243,7 +243,7 @@ checkbox:-moz-focusring {
 .devtools-menulist,
 .devtools-toolbarbutton,
 .devtools-button {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   min-height: 18px;
   text-shadow: none;
@@ -334,7 +334,7 @@ checkbox:-moz-focusring {
 
 /* Menu button styles (eg. web console filters) */
 .devtools-toolbarbutton[type=menu-button] > .toolbarbutton-menubutton-button {
-  -moz-appearance: none;
+  appearance: none;
   color: inherit;
   border-width: 0;
   -moz-box-orient: horizontal;
@@ -351,7 +351,7 @@ checkbox:-moz-focusring {
 }
 
 .devtools-menulist > .menulist-dropmarker {
-  -moz-appearance: none;
+  appearance: none;
   display: -moz-box;
   list-style-image: url("chrome://devtools/skin/images/dropmarker.svg");
   -moz-box-align: center;
@@ -360,7 +360,7 @@ checkbox:-moz-focusring {
 
 .devtools-toolbarbutton[type=menu] > .toolbarbutton-menu-dropmarker,
 .devtools-toolbarbutton[type=menu-button] > .toolbarbutton-menubutton-dropmarker {
-  -moz-appearance: none !important;
+  appearance: none !important;
   list-style-image: url("chrome://devtools/skin/images/dropmarker.svg");
   -moz-box-align: center;
   padding: 0 3px;
@@ -491,7 +491,7 @@ checkbox:-moz-focusring {
  * @TODO : Fix when https://bugzilla.mozilla.org/show_bug.cgi?id=1255116 lands
  */
 .menu-filter-button {
-  -moz-appearance: none;
+  appearance: none;
   background: rgba(128,128,128,0.1);
   border: none;
   border-radius: 2px;
@@ -519,7 +519,7 @@ checkbox:-moz-focusring {
 .devtools-textinput,
 .devtools-searchinput,
 .devtools-filterinput {
-  -moz-appearance: none;
+  appearance: none;
   margin: 1px 3px;
   border: 1px solid;
   border-radius: 2px;
diff --git a/devtools/client/themes/debugger.css b/devtools/client/themes/debugger.css
index 49a4478664..c50b20d6ee 100644
--- a/devtools/client/themes/debugger.css
+++ b/devtools/client/themes/debugger.css
@@ -61,7 +61,7 @@
 /* Firebug theme uses breakpoint icon istead of a checkbox */
 
 .theme-firebug #sources-pane .dbg-breakpoint-checkbox .checkbox-check {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background: url(chrome://devtools/skin/images/firebug/breakpoint.svg) no-repeat 50% 50%;
 }
@@ -326,7 +326,7 @@
 }
 
 .dbg-expression-button {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background: none;
   text-decoration: underline;
diff --git a/devtools/client/themes/devtools-browser.css b/devtools/client/themes/devtools-browser.css
index de846b8f3e..47f554e210 100644
--- a/devtools/client/themes/devtools-browser.css
+++ b/devtools/client/themes/devtools-browser.css
@@ -18,7 +18,7 @@
 
 .devtools-eyedropper-panel {
   pointer-events: none;
-  -moz-appearance: none;
+  appearance: none;
   width: 156px;
   height: 120px;
   background-color: transparent;
diff --git a/devtools/client/themes/floating-scrollbars-dark-theme.css b/devtools/client/themes/floating-scrollbars-dark-theme.css
index 042fe28cc2..e6b02ba641 100644
--- a/devtools/client/themes/floating-scrollbars-dark-theme.css
+++ b/devtools/client/themes/floating-scrollbars-dark-theme.css
@@ -7,7 +7,7 @@
    well as any overflow: scroll elements within the page, while excluding
    <select>. */
 *|*:not(html|select) > scrollbar {
-  -moz-appearance: none !important;
+  appearance: none !important;
   position: relative;
   background-color: transparent;
   background-image: none;
@@ -37,14 +37,14 @@
 
 *|*:not(html|select) > scrollbar thumb {
   background-color: rgba(170, 170, 170, .2) !important; /* --toolbar-tab-hover */
-  -moz-appearance: none !important;
+  appearance: none !important;
   border-width: 0px !important;
   border-radius: 3px !important;
 }
 
 *|*:root[platform="mac"] > scrollbar slider,
 *|*:root[platform="mac"] *|*:not(html|select) > scrollbar slider {
-  -moz-appearance: none !important;
+  appearance: none !important;
 }
 
 *|*:root[platform="win"] > scrollbar scrollbarbutton,
diff --git a/devtools/client/themes/floating-scrollbars-responsive-design.css b/devtools/client/themes/floating-scrollbars-responsive-design.css
index 7709bdd34c..183c441dfb 100644
--- a/devtools/client/themes/floating-scrollbars-responsive-design.css
+++ b/devtools/client/themes/floating-scrollbars-responsive-design.css
@@ -7,7 +7,7 @@
    well as any overflow: scroll elements within the page, while excluding
    <select>. */
 *|*:not(html|select) > scrollbar {
-  -moz-appearance: none !important;
+  appearance: none !important;
   position: relative;
   background-color: transparent;
   background-image: none;
@@ -31,11 +31,11 @@
 }
 
 *|*:not(html|select) > scrollbar slider {
-  -moz-appearance: none !important;
+  appearance: none !important;
 }
 
 *|*:not(html|select) > scrollbar thumb {
-  -moz-appearance: none !important;
+  appearance: none !important;
   background-color: rgba(0,0,0,0.2);
   border-width: 0px !important;
   border-radius: 3px !important;
diff --git a/devtools/client/themes/netmonitor.css b/devtools/client/themes/netmonitor.css
index d15970f4f4..a3146ebdc6 100644
--- a/devtools/client/themes/netmonitor.css
+++ b/devtools/client/themes/netmonitor.css
@@ -148,7 +148,7 @@
 }
 
 .requests-menu-header-button {
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   border-image: linear-gradient(transparent 15%,
                                 var(--theme-splitter-color) 15%,
diff --git a/devtools/client/themes/projecteditor/projecteditor.css b/devtools/client/themes/projecteditor/projecteditor.css
index e5d7f10a64..a6c5e96943 100644
--- a/devtools/client/themes/projecteditor/projecteditor.css
+++ b/devtools/client/themes/projecteditor/projecteditor.css
@@ -11,13 +11,13 @@
 }
 
 .arrow {
-  -moz-appearance: treetwisty;
+  appearance: treetwisty;
   width: 20px;
   height: 20px;
 }
 
 .arrow[open] {
-  -moz-appearance: treetwistyopen;
+  appearance: treetwistyopen;
 }
 
 .arrow[invisible] {
diff --git a/devtools/client/themes/responsivedesign.inc.css b/devtools/client/themes/responsivedesign.inc.css
index b06359ae1c..291233eb79 100644
--- a/devtools/client/themes/responsivedesign.inc.css
+++ b/devtools/client/themes/responsivedesign.inc.css
@@ -16,7 +16,7 @@
 }
 
 .devtools-responsiveui-toolbar {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   /* text color is textColor from dark theme, since no theme is applied to
    * the responsive toolbar.
@@ -29,7 +29,7 @@
 }
 
 .devtools-responsiveui-textinput {
-  -moz-appearance: none;
+  appearance: none;
   background: #333;
   color: #fff;
   border: 1px solid #111;
@@ -46,7 +46,7 @@
 
 .devtools-responsiveui-menulist,
 .devtools-responsiveui-toolbarbutton {
-  -moz-appearance: none;
+  appearance: none;
   -moz-box-align: center;
   min-width: 32px;
   min-height: 22px;
@@ -60,12 +60,12 @@
 }
 
 .devtools-responsiveui-menulist .menulist-editable-box {
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
 }
 
 .devtools-responsiveui-menulist html|*.menulist-editable-input {
-  -moz-appearance: none;
+  appearance: none;
   color: inherit;
   text-align: center;
 }
@@ -124,7 +124,7 @@
 }
 
 .devtools-responsiveui-menulist > .menulist-dropmarker {
-  -moz-appearance: none;
+  appearance: none;
   display: -moz-box;
   background-color: transparent;
   list-style-image: url("chrome://devtools/skin/images/dropmarker.svg");
@@ -134,7 +134,7 @@
 }
 
 .devtools-responsiveui-toolbarbutton[type=menu-button] > .toolbarbutton-menubutton-button {
-  -moz-appearance: none;
+  appearance: none;
   color: inherit;
   border-width: 0;
   border-inline-end: 1px solid hsla(210,8%,5%,.45);
@@ -152,7 +152,7 @@
 
 .devtools-responsiveui-toolbarbutton[type=menu] > .toolbarbutton-menu-dropmarker,
 .devtools-responsiveui-toolbarbutton[type=menu-button] > .toolbarbutton-menubutton-dropmarker {
-  -moz-appearance: none !important;
+  appearance: none !important;
   list-style-image: url("chrome://devtools/skin/images/dropmarker.svg");
   -moz-box-align: center;
   padding: 0 3px;
@@ -266,7 +266,7 @@
 }
 
 .devtools-responsiveui-hardware-buttons {
-  -moz-appearance: none;
+  appearance: none;
   padding: 20px;
 
   border: 1px solid #FFFFFF;
@@ -288,7 +288,7 @@
 
 .devtools-responsiveui-sleep-button {
   -moz-user-focus: ignore;
-  -moz-appearance: none;
+  appearance: none;
   /* compensate browserStack top padding */
   margin-top: -67px;
   margin-right: 10px;
@@ -316,7 +316,7 @@
 .devtools-responsiveui-volume-up-button,
 .devtools-responsiveui-volume-down-button {
   -moz-user-focus: ignore;
-  -moz-appearance: none;
+  appearance: none;
   border: 1px solid red;
   min-width: 8px;
   height: 40px;
diff --git a/devtools/client/themes/shadereditor.css b/devtools/client/themes/shadereditor.css
index 53ef94235a..196afe503c 100644
--- a/devtools/client/themes/shadereditor.css
+++ b/devtools/client/themes/shadereditor.css
@@ -28,7 +28,7 @@
 }
 
 .side-menu-widget-item-checkbox {
-  -moz-appearance: none;
+  appearance: none;
   opacity: 0;
   transition: opacity .15s ease-out 0s;
 }
@@ -43,7 +43,7 @@
 }
 
 .side-menu-widget-item-checkbox .checkbox-check {
-  -moz-appearance: none;
+  appearance: none;
   background-image: url(images/item-toggle.svg);
   background-color: transparent;
   width: 16px;
diff --git a/devtools/client/themes/splitters.css b/devtools/client/themes/splitters.css
index ade867d524..47f88263f6 100644
--- a/devtools/client/themes/splitters.css
+++ b/devtools/client/themes/splitters.css
@@ -32,7 +32,7 @@
 
 .devtools-horizontal-splitter,
 .devtools-side-splitter {
-  -moz-appearance: none;
+  appearance: none;
   background-image: none;
   border: 0;
   border-style: solid;
diff --git a/devtools/client/themes/toolbars.css b/devtools/client/themes/toolbars.css
index 9a755b4595..95bd95ae95 100644
--- a/devtools/client/themes/toolbars.css
+++ b/devtools/client/themes/toolbars.css
@@ -45,7 +45,7 @@
 /* Toolbars */
 .devtools-toolbar,
 .devtools-sidebar-tabs tabs {
-  -moz-appearance: none;
+  appearance: none;
   padding: 0;
   border-width: 0;
   border-bottom-width: 1px;
@@ -91,13 +91,13 @@
 
 /* In-tools sidebar */
 .devtools-sidebar-tabs {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0;
   height: 100%;
 }
 
 .devtools-sidebar-tabs > tabpanels {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   padding: 0;
   border: 0;
@@ -116,7 +116,7 @@
 }
 
 .devtools-sidebar-alltabs {
-  -moz-appearance: none;
+  appearance: none;
   height: 24px;
   line-height: 24px;
   padding: 0 4px;
@@ -136,7 +136,7 @@
 }
 
 .devtools-sidebar-tabs tabs > tab {
-  -moz-appearance: none;
+  appearance: none;
   /* We want to match the height of a toolbar with a toolbarbutton
    * First, we need to replicated the padding of toolbar (4px),
    * then we need to take the border of the buttons into account (1px).
diff --git a/devtools/client/themes/toolbox.css b/devtools/client/themes/toolbox.css
index e6704752bf..55b3b9374d 100644
--- a/devtools/client/themes/toolbox.css
+++ b/devtools/client/themes/toolbox.css
@@ -41,7 +41,7 @@
 /* Toolbox tabbar */
 
 .devtools-tabbar {
-  -moz-appearance: none;
+  appearance: none;
   min-height: 24px;
   border: 0px solid;
   border-bottom-width: 1px;
@@ -67,7 +67,7 @@
 /* Toolbox tabs */
 
 .devtools-tab {
-  -moz-appearance: none;
+  appearance: none;
   -moz-binding: url("chrome://global/content/bindings/general.xml#control-item");
   -moz-box-align: center;
   min-width: 32px;
@@ -224,7 +224,7 @@
 
 #toolbox-controls > button,
 #toolbox-dock-buttons > button {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   margin: 0 4px;
   min-width: 16px;
diff --git a/devtools/client/themes/tooltips.css b/devtools/client/themes/tooltips.css
index bf53bec276..698cf44718 100644
--- a/devtools/client/themes/tooltips.css
+++ b/devtools/client/themes/tooltips.css
@@ -108,7 +108,7 @@
 }
 
 .tooltip-xul-wrapper {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   overflow: visible;
   border-style: none;
diff --git a/devtools/client/themes/webaudioeditor.css b/devtools/client/themes/webaudioeditor.css
index 3ba9dad88c..3a9d3f61a9 100644
--- a/devtools/client/themes/webaudioeditor.css
+++ b/devtools/client/themes/webaudioeditor.css
@@ -125,7 +125,7 @@ text {
 .web-audio-inspector .error {
   background-image: url(images/alerticon-warning.png);
   background-size: 13px 12px;
-  -moz-appearance: none;
+  appearance: none;
   opacity: 0;
   transition: opacity .5s ease-out 0s;
 }
diff --git a/devtools/client/themes/webconsole.css b/devtools/client/themes/webconsole.css
index 5a3ebd7b8d..02139f7ed1 100644
--- a/devtools/client/themes/webconsole.css
+++ b/devtools/client/themes/webconsole.css
@@ -424,7 +424,7 @@ a {
   padding: 0;
   padding-inline-start: 20px;
   margin: 0;
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
 }
 
diff --git a/devtools/client/themes/widgets.css b/devtools/client/themes/widgets.css
index fca9c807c1..4c83b5fa07 100644
--- a/devtools/client/themes/widgets.css
+++ b/devtools/client/themes/widgets.css
@@ -122,7 +122,7 @@
 
 .scrollbutton-up,
 .scrollbutton-down {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   box-shadow: none;
   border: none;
@@ -133,7 +133,7 @@
 
 .scrollbutton-up > .toolbarbutton-icon,
 .scrollbutton-down > .toolbarbutton-icon {
-  -moz-appearance: none;
+  appearance: none;
   width: 7px;
   height: 16px;
   background-size: 14px 16px;
@@ -190,7 +190,7 @@
 
 .breadcrumbs-widget-item {
   background-color: transparent;
-  -moz-appearance: none;
+  appearance: none;
   min-height: 24px;
   min-width: 65px;
   margin: 0;
diff --git a/gfx/src/nsITheme.h b/gfx/src/nsITheme.h
index 9456a73947..26cc824ff4 100644
--- a/gfx/src/nsITheme.h
+++ b/gfx/src/nsITheme.h
@@ -51,7 +51,7 @@ public:
    * Draw the actual theme background.
    * @param aContext the context to draw into
    * @param aFrame the frame for the widget that we're drawing
-   * @param aWidgetType the -moz-appearance value to draw
+   * @param aWidgetType the appearance value to draw
    * @param aRect the rectangle defining the area occupied by the widget
    * @param aDirtyRect the rectangle that needs to be drawn
    */
@@ -148,8 +148,8 @@ public:
   /**
    * ThemeGeometryType values are used for describing themed nsIFrames in
    * calls to nsIWidget::UpdateThemeGeometries. We don't simply pass the
-   * -moz-appearance value ("widget type") of the frame because the widget may
-   * want to treat different frames with the same -moz-appearance differently
+   * appearance value ("widget type") of the frame because the widget may
+   * want to treat different frames with the same appearance differently
    * based on other properties of the frame. So we give the theme a first look
    * at the frame in nsITheme::ThemeGeometryTypeForWidget and pass the
    * returned ThemeGeometryType along to the widget.
diff --git a/layout/base/nsDisplayList.h b/layout/base/nsDisplayList.h
index 2f3f53b7fc..2c34b04cb6 100644
--- a/layout/base/nsDisplayList.h
+++ b/layout/base/nsDisplayList.h
@@ -653,7 +653,7 @@ public:
    * display list, except for themed widgets which are transformed or have
    * effects applied to them (e.g. CSS opacity or filters).
    *
-   * @param aWidgetType the -moz-appearance value for the themed widget
+   * @param aWidgetType the appearance value for the themed widget
    * @param aRect the device-pixel rect relative to the widget's displayRoot
    * for the themed widget
    */
@@ -1068,7 +1068,7 @@ public:
   void SetGlassDisplayItem(nsDisplayItem* aItem) {
     if (mGlassDisplayItem) {
       // Web pages or extensions could trigger this by using
-      // -moz-appearance:win-borderless-glass etc on their own elements.
+      // appearance:win-borderless-glass etc on their own elements.
       // Keep the first one, since that will be the background of the root
       // window
       NS_WARNING("Multiple glass backgrounds found?");
diff --git a/layout/base/nsPresContext.cpp b/layout/base/nsPresContext.cpp
index 2177090385..e19ff8bcd7 100644
--- a/layout/base/nsPresContext.cpp
+++ b/layout/base/nsPresContext.cpp
@@ -1681,7 +1681,7 @@ nsPresContext::ThemeChangedInternal()
   // :-moz-system-metric selectors (which requires eRestyle_Subtree).
   // Changes in theme can change system colors (whose changes are
   // properly reflected in computed style data), system fonts (whose
-  // changes are not), and -moz-appearance (whose changes likewise are
+  // changes are not), and appearance (whose changes likewise are
   // not), so we need to reflow.
   MediaFeatureValuesChanged(eRestyle_Subtree, NS_STYLE_HINT_REFLOW);
 
diff --git a/layout/forms/nsNumberControlFrame.cpp b/layout/forms/nsNumberControlFrame.cpp
index 1bae906b16..a1dfd3c083 100644
--- a/layout/forms/nsNumberControlFrame.cpp
+++ b/layout/forms/nsNumberControlFrame.cpp
@@ -418,7 +418,7 @@ nsNumberControlFrame::CreateAnonymousContent(nsTArray<ContentInfo>& aElements)
 
   if (StyleDisplay()->mAppearance == NS_THEME_TEXTFIELD) {
     // The author has elected to hide the spinner by setting this
-    // -moz-appearance. We will reframe if it changes.
+    // appearance. We will reframe if it changes.
     return rv;
   }
 
diff --git a/layout/style/nsStyleStruct.cpp b/layout/style/nsStyleStruct.cpp
index 77eb659377..359fb37ea8 100644
--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@@ -3193,8 +3193,8 @@ nsStyleDisplay::CalcDifference(const nsStyleDisplay& aNewData) const
       (mAppearance != NS_THEME_TEXTFIELD &&
        aNewData.mAppearance == NS_THEME_TEXTFIELD)) {
     // This is for <input type=number> where we allow authors to specify a
-    // |-moz-appearance:textfield| to get a control without a spinner. (The
-    // spinner is present for |-moz-appearance:number-input| but also other
+    // |appearance:textfield| to get a control without a spinner. (The
+    // spinner is present for |appearance:number-input| but also other
     // values such as 'none'.) We need to reframe since we want to use
     // nsTextControlFrame instead of nsNumberControlFrame if the author
     // specifies 'textfield'.
diff --git a/layout/style/res/forms.css b/layout/style/res/forms.css
index 0b35b1bdb1..77fe247fb7 100644
--- a/layout/style/res/forms.css
+++ b/layout/style/res/forms.css
@@ -83,7 +83,7 @@ label {
    need to match textfield background/border values here */
 
 input {
-  -moz-appearance: textfield;
+  appearance: textfield;
   /* The sum of border and padding on block-start and block-end
      must be the same here, for buttons, and for <select> (including its
      internal padding magic) */
@@ -146,7 +146,7 @@ textarea {
   cursor: text;
   resize: both;
   -moz-binding: url("chrome://global/content/platformHTMLBindings.xml#textAreas");
-  -moz-appearance: textfield-multiline;
+  appearance: textfield-multiline;
   text-indent: 0;
   user-select: text;
   text-shadow: none;
@@ -241,7 +241,7 @@ select {
   cursor: default;
   box-sizing: border-box;
   user-select: none;
-  -moz-appearance: menulist;
+  appearance: menulist;
   border-width: 2px;
   border-style: inset;
   text-indent: 0;
@@ -267,7 +267,7 @@ select[size][multiple] {
   vertical-align: text-bottom;
   padding-inline-start: 0;
   padding-inline-end: 0;
-  -moz-appearance: listbox;
+  appearance: listbox;
 }
 
 select[size="0"],
@@ -277,7 +277,7 @@ select[size="1"] {
   color: -moz-ComboboxText;
   vertical-align: baseline;
   padding: 0;
-  -moz-appearance: menulist;
+  appearance: menulist;
 }
 
 select > button {
@@ -287,7 +287,7 @@ select > button {
   background-image: url("arrow.gif") !important;
   background-repeat: no-repeat !important;
   background-position: center !important;
-  -moz-appearance: menulist-button;
+  appearance: menulist-button;
 
   /* Make sure to size correctly if the combobox has a non-auto height. */
   block-size: 100% ! important;
@@ -439,7 +439,7 @@ optgroup:disabled {
 
 /* hidden inputs */
 input[type="hidden"] {
-  -moz-appearance: none;
+  appearance: none;
   display: none !important;
   padding: 0;
   border: 0;
@@ -450,7 +450,7 @@ input[type="hidden"] {
 
 /* image buttons */
 input[type="image"] {
-  -moz-appearance: none;
+  appearance: none;
   padding: 0;
   border: none;
   background-color: transparent;
@@ -478,7 +478,7 @@ input[type="file"] {
   color: inherit;
 
   /* Revert rules which apply on all inputs. */
-  -moz-appearance: none;
+  appearance: none;
   -moz-binding: none;
   cursor: default;
 
@@ -534,7 +534,7 @@ input[type="file"]:dir(rtl) > xul|label {
 
 /* radio buttons */
 input[type="radio"] {
-  -moz-appearance: radio;
+  appearance: radio;
   margin-block-start: 3px;
   margin-block-end: 0px;
   margin-inline-start: 5px;
@@ -544,7 +544,7 @@ input[type="radio"] {
 
 /* check boxes */
 input[type="checkbox"] {
-  -moz-appearance: checkbox;
+  appearance: checkbox;
   margin-block-start: 3px;
   margin-block-end: 3px;
   margin-inline-start: 4px;
@@ -621,7 +621,7 @@ input[type="color"]:-moz-system-metric(color-picker-available),
 input[type="reset"],
 input[type="button"],
 input[type="submit"] {
-  -moz-appearance: button;
+  appearance: button;
   /* The sum of border and padding on block-start and block-end
      must be the same here, for text inputs, and for <select>.
      Note -moz-focus-inner padding does not affect button size. */
@@ -855,11 +855,11 @@ output:-moz-ui-invalid {
 }
 
 progress {
-  -moz-appearance: progressbar;
+  appearance: progressbar;
   display: inline-block;
   vertical-align: -0.2em;
 
-  /* Default style in case of there is -moz-appearance: none; */
+  /* Default style in case of there is appearance: none; */
   border: 2px solid;
   /* #e6e6e6 is a light gray. */
   -moz-border-top-colors: ThreeDShadow #e6e6e6;
@@ -877,16 +877,16 @@ progress {
   overflow: visible ! important;
   box-sizing: border-box ! important;
 
-  -moz-appearance: progresschunk;
+  appearance: progresschunk;
   height: 100%;
   width: 100%;
 
-  /* Default style in case of there is -moz-appearance: none; */
+  /* Default style in case of there is appearance: none; */
   background-color: #0064b4; /* blue */
 }
 
 meter {
-  -moz-appearance: meterbar;
+  appearance: meterbar;
   display: inline-block;
   vertical-align: -0.2em;
 
@@ -900,7 +900,7 @@ meter {
   position: static ! important;
   overflow: visible ! important;
 
-  -moz-appearance: meterchunk;
+  appearance: meterchunk;
   height: 100%;
   width: 100%;
 }
@@ -919,7 +919,7 @@ meter {
 }
 
 input[type=range] {
-  -moz-appearance: range;
+  appearance: range;
   display: inline-block;
   inline-size: 12em;
   block-size: 1.3em;
@@ -1033,10 +1033,10 @@ input[type=range]::-moz-range-progress {
  * properties are ignored.
  */
 input[type=range]::-moz-range-thumb {
-  /* Native theming is atomic for range. Set -moz-appearance on the range
-   * to get rid of it. The thumb's -moz-appearance is fixed.
+  /* Native theming is atomic for range. Set appearance on the range
+   * to get rid of it. The thumb's appearance is fixed.
    */
-  -moz-appearance: range-thumb !important;
+  appearance: range-thumb !important;
   /* Prevent styling that would change the type of frame we construct. */
   display: inline-block !important;
   float: none !important;
@@ -1066,7 +1066,7 @@ input[type=number]::-moz-number-text {
   display: block; /* Flex items must be block-level. Normally we do fixup in
                      the style system to ensure this, but that fixup is disabled
                      inside of form controls. So, we hardcode display here. */
-  -moz-appearance: none;
+  appearance: none;
   /* work around autofocus bug 939248 on initial load */
   -moz-user-modify: read-write;
   /* This pseudo-element is also an 'input' element (nested inside and
@@ -1108,7 +1108,7 @@ input[type=number]::-moz-number-spin-box {
 
 input[type=number]::-moz-number-spin-up {
   writing-mode: horizontal-tb;
-  -moz-appearance: spinner-upbutton;
+  appearance: spinner-upbutton;
   display: block; /* bug 926670 */
   flex: none;
   cursor: default;
@@ -1126,7 +1126,7 @@ input[type=number]::-moz-number-spin-up {
 
 input[type=number]::-moz-number-spin-down {
   writing-mode: horizontal-tb;
-  -moz-appearance: spinner-downbutton;
+  appearance: spinner-downbutton;
   display: block; /* bug 926670 */
   flex: none;
   cursor: default;
diff --git a/layout/style/res/number-control.css b/layout/style/res/number-control.css
index b4c784cf27..32303553a0 100644
--- a/layout/style/res/number-control.css
+++ b/layout/style/res/number-control.css
@@ -8,7 +8,7 @@
  */
 
 input[type="number"] {
-  -moz-appearance: number-input;
+  appearance: number-input;
   /* Has to revert some properties applied by the generic input rule. */
   -moz-binding: none;
   inline-size: 20ch; /* It'd be nice if this matched the default inline-size
diff --git a/layout/svg/svg.css b/layout/svg/svg.css
index 79aed0482c..d6b49b0a5d 100644
--- a/layout/svg/svg.css
+++ b/layout/svg/svg.css
@@ -32,7 +32,7 @@ svg:not(:root), symbol, image, marker, pattern, foreignObject {
 }
 
 foreignObject {
-  -moz-appearance: none ! important;
+  appearance: none ! important;
   margin: 0 ! important;
   padding: 0 ! important;
   border-width: 0 ! important;
@@ -41,7 +41,7 @@ foreignObject {
 
 @media all and (-moz-is-resource-document) {
  foreignObject *|* {
-   -moz-appearance: none !important;
+   appearance: none !important;
  }
 }
 
diff --git a/layout/xul/tree/nsTreeBodyFrame.cpp b/layout/xul/tree/nsTreeBodyFrame.cpp
index 6af20efe90..34f7acf5f8 100644
--- a/layout/xul/tree/nsTreeBodyFrame.cpp
+++ b/layout/xul/tree/nsTreeBodyFrame.cpp
@@ -2066,7 +2066,7 @@ nsTreeBodyFrame::GetTwistyRect(int32_t aRowIndex,
   // determine the twisty rect's true width.  This is done by examining the style context for
   // a width first.  If it has one, we use that.  If it doesn't, we use the image's natural width.
   // If the image hasn't loaded and if no width is specified, then we just bail. If there is
-  // a -moz-appearance involved, adjust the rect by the minimum widget size provided by
+  // an `appearance` involved, adjust the rect by the minimum widget size provided by
   // the theme implementation.
   aImageRect = GetImageSize(aRowIndex, aColumn, true, aTwistyContext);
   if (aImageRect.height > aTwistyRect.height)
@@ -2855,8 +2855,8 @@ nsTreeBodyFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
   // properly, we also need the tree to be themed as a source list.
   if (selection && treeFrame && theme &&
       treeFrame->StyleDisplay()->mAppearance == NS_THEME_MAC_SOURCE_LIST) {
-    // Loop through our onscreen rows. If the row is selected and a
-    // -moz-appearance is provided, RegisterThemeGeometry might be necessary.
+    // Loop through our onscreen rows. If the row is selected and an
+    // `appearance` is provided, RegisterThemeGeometry might be necessary.
     const auto end = std::min(mRowCount, LastVisibleRow() + 1);
     for (auto i = FirstVisibleRow(); i < end; i++) {
       bool isSelected;
@@ -3197,7 +3197,7 @@ nsTreeBodyFrame::PaintSeparator(int32_t              aRowIndex,
 
   DrawResult result = DrawResult::SUCCESS;
 
-  // use -moz-appearance if provided.
+  // use appearance if provided.
   if (useTheme) {
     nsRect dirty;
     dirty.IntersectRect(aSeparatorRect, aDirtyRect);
diff --git a/mailnews/db/gloda/content/glodacomplete.css b/mailnews/db/gloda/content/glodacomplete.css
index 25dab6c038..18a3f6b84a 100644
--- a/mailnews/db/gloda/content/glodacomplete.css
+++ b/mailnews/db/gloda/content/glodacomplete.css
@@ -13,7 +13,7 @@ panel[type="glodacomplete-richlistbox"] {
 .autocomplete-richlistbox {
   -moz-binding: url("chrome://global/content/bindings/autocomplete.xml#autocomplete-richlistbox");
   -moz-user-focus: ignore;
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .autocomplete-richlistbox > scrollbox {
diff --git a/toolkit/content/menulist.css b/toolkit/content/menulist.css
index ae6166d1b8..ac9cb4e5cc 100644
--- a/toolkit/content/menulist.css
+++ b/toolkit/content/menulist.css
@@ -5,7 +5,7 @@
 @namespace html url("http://www.w3.org/1999/xhtml"); /* namespace for HTML elements */
 
 html|*.menulist-editable-input {
-  -moz-appearance: none !important;
+  appearance: none !important;
   background: transparent ! important;
   -moz-box-flex: 1;
 }
diff --git a/toolkit/content/textbox.css b/toolkit/content/textbox.css
index a16b4fd436..f55a97e2c3 100644
--- a/toolkit/content/textbox.css
+++ b/toolkit/content/textbox.css
@@ -6,7 +6,7 @@
 @namespace html url("http://www.w3.org/1999/xhtml"); /* namespace for HTML elements */
 
 html|*.textbox-input {
-  -moz-appearance: none !important;
+  appearance: none !important;
   text-align: inherit;
   text-shadow: inherit;
   box-sizing: border-box;
@@ -14,7 +14,7 @@ html|*.textbox-input {
 }
 
 html|*.textbox-textarea {
-  -moz-appearance: none !important;
+  appearance: none !important;
   text-shadow: inherit;
   box-sizing: border-box;
   -moz-box-flex: 1;
diff --git a/toolkit/content/widgets/datetimebox.css b/toolkit/content/widgets/datetimebox.css
index 4661aaebe2..55bbb276e1 100644
--- a/toolkit/content/widgets/datetimebox.css
+++ b/toolkit/content/widgets/datetimebox.css
@@ -6,7 +6,7 @@
 @namespace xul url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 .datetime-input-box-wrapper {
-  -moz-appearance: none;
+  appearance: none;
   display: inline-flex;
   flex: 1;
   cursor: default;
@@ -22,7 +22,7 @@
 }
 
 .datetime-input {
-  -moz-appearance: none;
+  appearance: none;
   text-align: center;
   padding: 0;
   border: 0;
diff --git a/toolkit/content/xul.css b/toolkit/content/xul.css
index 33dbd2107e..dd1653cd58 100644
--- a/toolkit/content/xul.css
+++ b/toolkit/content/xul.css
@@ -302,7 +302,7 @@ toolbar[type="menubar"][autohide="true"] {
 toolbar[type="menubar"][autohide="true"][inactive="true"]:not([customizing="true"]) {
   min-height: 0 !important;
   height: 0 !important;
-  -moz-appearance: none !important;
+  appearance: none !important;
   border-style: none !important;
 }
 %endif
@@ -942,7 +942,7 @@ menulist {
 
 menulist[popuponly="true"] {
   -moz-binding: url("chrome://global/content/bindings/menulist.xml#menulist-popuponly");
-  -moz-appearance: none !important;
+  appearance: none !important;
   margin: 0 !important;
   height: 0 !important;
   border: 0 !important;
diff --git a/toolkit/jetpack/sdk/ui/toolbar/view.js b/toolkit/jetpack/sdk/ui/toolbar/view.js
index 4ef0c3d465..9d1a51e672 100644
--- a/toolkit/jetpack/sdk/ui/toolbar/view.js
+++ b/toolkit/jetpack/sdk/ui/toolbar/view.js
@@ -125,7 +125,7 @@ const addView = curry((options, {document, window}) => {
   toolbar.setAttribute("id", "inner-" + options.id);
   toolbar.setAttribute("defaultset", options.items.join(","));
   toolbar.setAttribute("customizable", "true");
-  toolbar.setAttribute("style", "-moz-appearance: none; overflow: hidden");
+  toolbar.setAttribute("style", "appearance: none; overflow: hidden");
   toolbar.setAttribute("mode", "icons");
   toolbar.setAttribute("iconsize", "small");
   toolbar.setAttribute("context", "toolbar-context-menu");
diff --git a/toolkit/themes/faststripe/global/button.css b/toolkit/themes/faststripe/global/button.css
index 39f3227119..dafbf29d2f 100644
--- a/toolkit/themes/faststripe/global/button.css
+++ b/toolkit/themes/faststripe/global/button.css
@@ -11,7 +11,7 @@
 /* :::::::::: button :::::::::: */
 
 button {
-  /*-moz-appearance: button;*/
+  /*appearance: button;*/
   margin: 3px 7px 3px 7px;
   min-width: 6.3em;
   border: 1px solid;
@@ -86,7 +86,7 @@ button[type="menu-button"] {
 
 .button-menu-dropmarker,
 .button-menubutton-dropmarker {
-  -moz-appearance: none !important;
+  appearance: none !important;
   margin: 1px;
   background-color: transparent !important;
   border: none !important;
diff --git a/toolkit/themes/faststripe/global/groupbox.css b/toolkit/themes/faststripe/global/groupbox.css
index ae1e80fc94..5584693461 100644
--- a/toolkit/themes/faststripe/global/groupbox.css
+++ b/toolkit/themes/faststripe/global/groupbox.css
@@ -11,7 +11,7 @@
 /* ::::: groupbox ::::: */
 
 groupbox {
-  -moz-appearance: groupbox;
+  appearance: groupbox;
   border: 1px solid gray;
   border-radius: 3px;
   margin: 3px;
@@ -28,7 +28,7 @@ caption {
 }
 
 tabpanels caption {
-  -moz-appearance: tabpanel;
+  appearance: tabpanel;
 }
 
 /* !important is needed to override label in global.css */
diff --git a/toolkit/themes/faststripe/global/menu.css b/toolkit/themes/faststripe/global/menu.css
index 4f58205228..d083ac3544 100644
--- a/toolkit/themes/faststripe/global/menu.css
+++ b/toolkit/themes/faststripe/global/menu.css
@@ -12,7 +12,7 @@
 
 menu,
 menuitem {
-  -moz-appearance: menuitem;
+  appearance: menuitem;
   -moz-box-align: center;
   color: MenuText;
   font: menu;
@@ -47,7 +47,7 @@ menuitem.spell-suggestion {
 
 .menu-text {
   padding-inline-start: 1.45em !important;
-  -moz-appearance: menuitemtext;
+  appearance: menuitemtext;
 }
 
 .menu-text,
@@ -83,7 +83,7 @@ menu.menu-iconic > .menu-iconic-left,
 menuitem.menuitem-iconic > .menu-iconic-left,
 menu.menu-iconic > .menu-iconic-right,
 menuitem.menuitem-iconic > .menu-iconic-right {
-  -moz-appearance: menuimage;
+  appearance: menuimage;
   padding-top: 2px;
 }
 
@@ -146,7 +146,7 @@ menuitem[_moz-menuactive="true"] {
 
 menulist > menupopup > menuitem,
 menulist > menupopup > menu {
-  -moz-appearance: none;
+  appearance: none;
   border: 1px solid transparent;
   padding: 1px 5px;
   max-width: none;
diff --git a/toolkit/themes/faststripe/global/popup.css b/toolkit/themes/faststripe/global/popup.css
index b321347f81..3cb0a5d6e4 100644
--- a/toolkit/themes/faststripe/global/popup.css
+++ b/toolkit/themes/faststripe/global/popup.css
@@ -23,7 +23,7 @@ menupopup,
 /* auto complete popups don't render well as vista menus */
 popup:not([type="autocomplete"])
 {
-  -moz-appearance: menupopup;
+  appearance: menupopup;
 }
 
 menupopup > menu > menupopup,
diff --git a/toolkit/themes/faststripe/global/radio.css b/toolkit/themes/faststripe/global/radio.css
index f2d399e3d5..c1e2c8ee8d 100644
--- a/toolkit/themes/faststripe/global/radio.css
+++ b/toolkit/themes/faststripe/global/radio.css
@@ -11,7 +11,7 @@
 /* ::::: radio ::::: */
 
 radio {
-  -moz-appearance: radio-container;
+  appearance: radio-container;
   -moz-box-align: center;
   margin: 2px 4px;
   padding-top: 1px;
diff --git a/toolkit/themes/faststripe/global/xulscrollbars.css b/toolkit/themes/faststripe/global/xulscrollbars.css
index 141327c2f0..3c110a1ba8 100644
--- a/toolkit/themes/faststripe/global/xulscrollbars.css
+++ b/toolkit/themes/faststripe/global/xulscrollbars.css
@@ -21,7 +21,7 @@ scrollbar {
 
 scrollbar[orient="vertical"] 
 {
-   -moz-appearance: scrollbar-vertical;
+   appearance: scrollbar-vertical;
   border-left: none;
   border-right: none;
   border-top: 1px solid #555555;
@@ -62,7 +62,7 @@ scrollbarbutton:hover:active, scrollbarbutton[active="true"] {
 /* ::::: square at the corner of two scrollbars ::::: */
 
 scrollcorner { 
-  /* XXX -moz-appearance: scrollcorner; */
+  /* XXX appearance: scrollcorner; */
   -moz-binding: url(chrome://global/content/bindings/scrollbar.xml#scrollbar-base);
   width: 16px;
   cursor: default;
@@ -72,7 +72,7 @@ scrollcorner {
 /* ..... increment .... */
 
 scrollbarbutton[type="increment"] {
-  -moz-appearance: scrollbarbutton-right;
+  appearance: scrollbarbutton-right;
   background-image: url("chrome://global/skin/arrow/arrow-rit.gif")
 }
 
@@ -81,7 +81,7 @@ scrollbarbutton[type="increment"][disabled="true"] {
 }
 
 scrollbar[orient="vertical"] > scrollbarbutton[type="increment"] {
-  -moz-appearance: scrollbarbutton-down;
+  appearance: scrollbarbutton-down;
   background-image: url("chrome://global/skin/arrow/arrow-dn.gif")
 }
 
@@ -92,7 +92,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="increment"][disabled="true"
 /* ..... decrement .... */
 
 scrollbarbutton[type="decrement"] {
-  -moz-appearance: scrollbarbutton-left;
+  appearance: scrollbarbutton-left;
    background-image: url("chrome://global/skin/arrow/arrow-lft.gif")
 }
 
@@ -101,7 +101,7 @@ scrollbarbutton[type="decrement"][disabled="true"] {
 }
 
 scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"] {
-  -moz-appearance: scrollbarbutton-up;
+  appearance: scrollbarbutton-up;
    background-image: url("chrome://global/skin/arrow/arrow-up.gif")
 }
 
@@ -116,7 +116,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   /* ::::: scrollbar ::::: */
 
   html|div scrollbar {
-    -moz-appearance: scrollbar-horizontal;
+    appearance: scrollbar-horizontal;
     -moz-binding: url("chrome://global/content/bindings/scrollbar.xml#scrollbar");
     cursor: default;
     background: url("chrome://global/skin/scrollbar/slider.gif") scrollbar;
@@ -124,7 +124,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
 
   html|div scrollbar[orient="vertical"] 
   {
-     -moz-appearance: scrollbar-vertical;
+     appearance: scrollbar-vertical;
   }
 
   /* ::::: borders for thumb and buttons ::::: */
@@ -142,12 +142,12 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   /* ::::: thumb (horizontal) ::::: */
 
   html|div thumb {
-    -moz-appearance: scrollbarthumb-vertical;
+    appearance: scrollbarthumb-vertical;
     min-height: 8px;
   }
 
   html|div thumb[orient="horizontal"] {
-    -moz-appearance: scrollbarthumb-horizontal;
+    appearance: scrollbarthumb-horizontal;
     min-width: 8px;
   }
 
@@ -170,7 +170,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   /* ..... increment .... */
 
   html|div scrollbarbutton[type="increment"] {
-    -moz-appearance: scrollbarbutton-right;
+    appearance: scrollbarbutton-right;
     background-image: url("chrome://global/skin/arrow/arrow-rit.gif")
   }
 
@@ -179,7 +179,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   }
 
   html|div scrollbar[orient="vertical"] > scrollbarbutton[type="increment"] {
-    -moz-appearance: scrollbarbutton-down;
+    appearance: scrollbarbutton-down;
     background-image: url("chrome://global/skin/arrow/arrow-dn.gif")
   }
 
@@ -190,7 +190,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   /* ..... decrement .... */
 
   html|div scrollbarbutton[type="decrement"] {
-    -moz-appearance: scrollbarbutton-left;
+    appearance: scrollbarbutton-left;
      background-image: url("chrome://global/skin/arrow/arrow-lft.gif")
   }
 
@@ -199,7 +199,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   }
 
   html|div scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"] {
-    -moz-appearance: scrollbarbutton-up;
+    appearance: scrollbarbutton-up;
      background-image: url("chrome://global/skin/arrow/arrow-up.gif")
   }
 
diff --git a/toolkit/themes/linux/global/alerts/alert.css b/toolkit/themes/linux/global/alerts/alert.css
index 7d09f02920..807828588a 100644
--- a/toolkit/themes/linux/global/alerts/alert.css
+++ b/toolkit/themes/linux/global/alerts/alert.css
@@ -16,7 +16,7 @@
 }
 
 .alertCloseButton {
-  -moz-appearance: none;
+  appearance: none;
   height: 16px;
   padding: 4px 2px;
   width: 16px;
diff --git a/toolkit/themes/linux/global/autocomplete.css b/toolkit/themes/linux/global/autocomplete.css
index 0b4536c32b..61a4555b20 100644
--- a/toolkit/themes/linux/global/autocomplete.css
+++ b/toolkit/themes/linux/global/autocomplete.css
@@ -18,7 +18,7 @@ textbox:not(.padded) {
 }
 
 textbox[enablehistory="true"] {
-  -moz-appearance: none;
+  appearance: none;
   border: 0;
   background-color: transparent;
 }
@@ -32,7 +32,7 @@ textbox[nomatch="true"][highlightnonmatches="true"] {
 }
 
 textbox[enablehistory="true"] > .autocomplete-textbox-container {
-  -moz-appearance: menulist-textfield;
+  appearance: menulist-textfield;
 }
 
 textbox:not(.padded) .textbox-input-box {
@@ -52,7 +52,7 @@ panel[type="autocomplete-richlistbox"],
   padding: 0;
   color: -moz-FieldText;
   background-color: -moz-Field;
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .autocomplete-history-popup {
@@ -62,13 +62,13 @@ panel[type="autocomplete-richlistbox"],
 /* ::::: tree ::::: */
 
 .autocomplete-tree {
-  -moz-appearance: none !important;
+  appearance: none !important;
   border: none !important;
   background-color: transparent !important;
 }
 
 .autocomplete-treecol {
-  -moz-appearance: none !important;
+  appearance: none !important;
   margin: 0 !important;
   border: none !important;
   padding: 0 !important;
@@ -76,7 +76,7 @@ panel[type="autocomplete-richlistbox"],
 
 /* GTK calculates space for a sort arrow */
 .autocomplete-treecol > .treecol-sortdirection {
-  -moz-appearance: none !important;
+  appearance: none !important;
 }
 
 .autocomplete-treebody::-moz-tree-cell-text {
@@ -99,7 +99,7 @@ treechildren.autocomplete-treebody::-moz-tree-cell-text(selected) {
 /* ::::: richlistbox autocomplete ::::: */
 
 .autocomplete-richlistbox {
-  -moz-appearance: none;
+  appearance: none;
   margin: 1px;
   background-color: transparent;
 }
diff --git a/toolkit/themes/linux/global/button.css b/toolkit/themes/linux/global/button.css
index 620247587a..bb4fcedf49 100644
--- a/toolkit/themes/linux/global/button.css
+++ b/toolkit/themes/linux/global/button.css
@@ -11,7 +11,7 @@
 /* :::::::::: button :::::::::: */
 
 button {
-  -moz-appearance: button;
+  appearance: button;
   margin: 1px 5px 2px 5px;
   min-width: 6.3em;
   border: 3px solid;
@@ -25,7 +25,7 @@ button {
 }
 
 .button-box {
-  -moz-appearance: button-focus;
+  appearance: button-focus;
   border: 1px solid transparent;
   padding-top: 1px;
   padding-bottom: 2px;
@@ -113,7 +113,7 @@ button[disabled="true"] > .button-box {
 /* ::::: menu/menu-button buttons ::::: */
 
 button[type="menu-button"] {
-  -moz-appearance: dualbutton;
+  appearance: dualbutton;
 }
 
 .button-menubutton-button {
@@ -122,7 +122,7 @@ button[type="menu-button"] {
 
 .button-menu-dropmarker,
 .button-menubutton-dropmarker {
-  -moz-appearance: toolbarbutton-dropdown !important;
+  appearance: toolbarbutton-dropdown !important;
 }
 
 .button-menubutton-dropmarker {
@@ -141,7 +141,7 @@ button[type="disclosure"] {
   border: 0px !important;
   margin: 0px !important;
   padding: 0px !important;
-  -moz-appearance: none;
+  appearance: none;
   list-style-image: url("chrome://global/skin/tree/twisty-clsd.png");
   min-width: 0px !important;
   background-color: transparent;
diff --git a/toolkit/themes/linux/global/checkbox.css b/toolkit/themes/linux/global/checkbox.css
index a4e07448ec..2d214bbd44 100644
--- a/toolkit/themes/linux/global/checkbox.css
+++ b/toolkit/themes/linux/global/checkbox.css
@@ -11,7 +11,7 @@
 /* ::::: checkbox ::::: */
 
 checkbox {
-  -moz-appearance: checkbox-container;
+  appearance: checkbox-container;
   margin: 2px 4px;
   border-left: 2px transparent;
   border-right: 2px transparent;
@@ -27,7 +27,7 @@ checkbox {
    mark. */
 
 .checkbox-spacer-box {
-  -moz-appearance: checkbox;
+  appearance: checkbox;
   -moz-box-align: center;
   margin: 2px;
   border-right: 2px solid transparent;
@@ -38,7 +38,7 @@ checkbox {
 }
 
 .checkbox-label-box {
-  -moz-appearance: checkbox-label;
+  appearance: checkbox-label;
 }
 
 .checkbox-icon[src] {
diff --git a/toolkit/themes/linux/global/colorpicker.css b/toolkit/themes/linux/global/colorpicker.css
index 5870ed5d1b..0c7c812b58 100644
--- a/toolkit/themes/linux/global/colorpicker.css
+++ b/toolkit/themes/linux/global/colorpicker.css
@@ -13,7 +13,7 @@
 /* colorpicker button */
 
 colorpicker[type="button"] {
-  -moz-appearance: button;
+  appearance: button;
   width: 38px;
   height: 24px;
 }
diff --git a/toolkit/themes/linux/global/dropmarker.css b/toolkit/themes/linux/global/dropmarker.css
index 5b44ac40ea..66ac5db096 100644
--- a/toolkit/themes/linux/global/dropmarker.css
+++ b/toolkit/themes/linux/global/dropmarker.css
@@ -3,5 +3,5 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 dropmarker {
-  -moz-appearance: menulist-button;
+  appearance: menulist-button;
 }
diff --git a/toolkit/themes/linux/global/findBar.css b/toolkit/themes/linux/global/findBar.css
index 4a9df23aec..db5be8c8b1 100644
--- a/toolkit/themes/linux/global/findBar.css
+++ b/toolkit/themes/linux/global/findBar.css
@@ -26,13 +26,13 @@ findbar[hidden] {
 /* find-next button */
 
 .findbar-find-next > .toolbarbutton-icon {
-  -moz-appearance: button-arrow-next;
+  appearance: button-arrow-next;
 }
 
 /* find-previous button */
 
 .findbar-find-previous > .toolbarbutton-icon {
-  -moz-appearance: button-arrow-previous;
+  appearance: button-arrow-previous;
 }
 
 /* highlight button */
@@ -74,7 +74,7 @@ findbar[hidden] {
 }
 
 .findbar-textbox {
-  -moz-appearance: none;
+  appearance: none;
   border: 1px solid ThreeDShadow;
   box-shadow: 0 0 1px 0 ThreeDShadow inset;
   margin: 0;
diff --git a/toolkit/themes/linux/global/global.css b/toolkit/themes/linux/global/global.css
index 947b45107f..57adbed2ee 100644
--- a/toolkit/themes/linux/global/global.css
+++ b/toolkit/themes/linux/global/global.css
@@ -48,7 +48,7 @@ page,
 dialog,
 wizard,
 prefwindow {
-  -moz-appearance: window;
+  appearance: window;
   background-color: -moz-Dialog;
   color: -moz-DialogText;
   font: message-box;
@@ -98,7 +98,7 @@ iframe {
 /* ::::: statusbar ::::: */
 
 statusbar {
-  -moz-appearance: statusbar;
+  appearance: statusbar;
   border-top: 1px solid ThreeDLightShadow;
   border-left: 1px solid ThreeDShadow;
   border-right: 1px solid ThreeDHighlight;
@@ -108,7 +108,7 @@ statusbar {
 }
 
 statusbarpanel {
-  -moz-appearance: statusbarpanel;
+  appearance: statusbarpanel;
   -moz-box-align: center;
   -moz-box-pack: center;
   border-left: 1px solid ThreeDHighlight;
@@ -121,7 +121,7 @@ statusbarpanel {
 .statusbar-resizerpanel {
   -moz-box-align: end;
   -moz-box-pack: end;
-  -moz-appearance: resizerpanel;
+  appearance: resizerpanel;
   padding: 0;
   border: none;
 }
@@ -157,7 +157,7 @@ toolbar[mode="text"] .toolbarbutton-text {
 :root:-moz-lwtheme,
 [lwthemefooter="true"],
 statusbarpanel:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 sidebarheader:-moz-lwtheme {
@@ -219,7 +219,7 @@ separator.groove[orient="vertical"] {
 }
     
 .plain {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0 !important;
   border: none;
   padding: 0;
@@ -306,7 +306,7 @@ popupnotificationcontent {
   background-image: url("chrome://global/skin/icons/autoscroll.png");
   background-color: transparent;
   background-position: right top;
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .autoscroller[scrolldir="NS"] {
@@ -321,7 +321,7 @@ popupnotificationcontent {
 
 %ifdef MOZ_AUSTRALIS
 .close-icon {
-  -moz-appearance: none;
+  appearance: none;
   height: 16px;
   width: 16px;
   background-image: -moz-image-rect(url("chrome://global/skin/icons/close.svg"), 0, 16, 16, 0);
diff --git a/toolkit/themes/linux/global/in-content/common.css b/toolkit/themes/linux/global/in-content/common.css
index 75035d2e52..917716fa7a 100644
--- a/toolkit/themes/linux/global/in-content/common.css
+++ b/toolkit/themes/linux/global/in-content/common.css
@@ -21,11 +21,11 @@ xul|menulist {
 
 xul|button > xul|*.button-box,
 xul|menulist > xul|*.menulist-label-box {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 xul|button[type="menu"] > xul|*.button-box > xul|*.button-menu-dropmarker {
-  -moz-appearance: none !important;
+  appearance: none !important;
 }
 
 xul|*.help-button > xul|*.button-box > xul|*.button-icon {
@@ -75,7 +75,7 @@ xul|*.radio-check[selected] {
 }
 
 xul|*.radio-label-box {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 /* Override OS-theme-based color to make it visible
@@ -86,7 +86,7 @@ xul|checkbox:not([disabled="true"]):hover {
 }
 
 xul|*.numberbox-input-box {
-  -moz-appearance: none;
+  appearance: none;
   border-width: 0;
 }
 
@@ -102,7 +102,7 @@ xul|checkbox:-moz-focusring > xul|*.checkbox-label-box {
 }
 
 xul|spinbuttons {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 xul|treechildren::-moz-tree-row(multicol, odd) {
diff --git a/toolkit/themes/linux/global/inContentUI.css b/toolkit/themes/linux/global/inContentUI.css
index afcef9274e..4acdadcc11 100644
--- a/toolkit/themes/linux/global/inContentUI.css
+++ b/toolkit/themes/linux/global/inContentUI.css
@@ -11,7 +11,7 @@
 
 /* Page background */
 *|*:root {
-  -moz-appearance: none;
+  appearance: none;
   padding: 18px;
   background-color: Window;
   background-image: /* Texture */
diff --git a/toolkit/themes/linux/global/listbox.css b/toolkit/themes/linux/global/listbox.css
index dbce007cee..a22f7064cd 100644
--- a/toolkit/themes/linux/global/listbox.css
+++ b/toolkit/themes/linux/global/listbox.css
@@ -11,7 +11,7 @@
 /* ::::: listbox ::::: */
 
 listbox {
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 2px 4px;
   border: 2px solid;
   -moz-border-top-colors: ThreeDShadow ThreeDDarkShadow;
@@ -54,7 +54,7 @@ listbox:focus > listitem[selected="true"] {
 /* ::::: listheader ::::: */
 
 listheader { 
-  -moz-appearance: treeheadercell;
+  appearance: treeheadercell;
   -moz-box-align: center;
   border: 2px solid;
   -moz-border-top-colors: ThreeDHighlight ThreeDLightShadow;
@@ -98,7 +98,7 @@ listheader[sortable="true"]:hover:active {
 /* ..... sort direction icon ..... */
 
 .listheader-sortdirection {
-  -moz-appearance: treeheadersortarrow;
+  appearance: treeheadersortarrow;
 }
 
 /* ::::: listcell ::::: */
@@ -123,7 +123,7 @@ listheader[sortable="true"]:hover:active {
 /* ::::: listcell checkbox ::::: */
 
 .listcell-check {
-  -moz-appearance: checkbox;
+  appearance: checkbox;
   -moz-box-align: center;
   margin: 0px 2px;
   border: 1px solid -moz-DialogText;
diff --git a/toolkit/themes/linux/global/menu.css b/toolkit/themes/linux/global/menu.css
index 06e3b217bd..1735ecf181 100644
--- a/toolkit/themes/linux/global/menu.css
+++ b/toolkit/themes/linux/global/menu.css
@@ -14,7 +14,7 @@ menu,
 menuitem,
 menucaption,
 .splitmenu-menuitem {
-  -moz-appearance: menuitem;
+  appearance: menuitem;
   -moz-box-align: center;
   max-width: 42em;
   color: MenuText;
@@ -142,7 +142,7 @@ menucaption > .menu-iconic-text {
   /* These next two rules are needed to prevent inheritance and thus ugliness */
   list-style-image: none;
   -moz-image-region: auto;
-  -moz-appearance: menuarrow;
+  appearance: menuarrow;
 }
 
 .menubar-left {
@@ -168,23 +168,23 @@ menulist > menupopup > menu > .menu-iconic-left {
 /* ::::: checkbox menuitem ::::: */
 
 menuitem[checked="true"] {
-  -moz-appearance: checkmenuitem !important;
+  appearance: checkmenuitem !important;
 }
 
 menuitem[type="checkbox"] {
-  -moz-appearance: checkmenuitem !important;
+  appearance: checkmenuitem !important;
 }
 
 /* ::::: radio menuitem ::::: */
 
 menuitem[type="radio"] {
-  -moz-appearance: radiomenuitem !important;
+  appearance: radiomenuitem !important;
 }
 
 /* ::::: menuseparator ::::: */
 
 menuseparator {
-  -moz-appearance: menuseparator;
+  appearance: menuseparator;
 }
 
 /* ::::: autocomplete ::::: */
diff --git a/toolkit/themes/linux/global/menulist.css b/toolkit/themes/linux/global/menulist.css
index 73c1dfd49a..20620b6c90 100644
--- a/toolkit/themes/linux/global/menulist.css
+++ b/toolkit/themes/linux/global/menulist.css
@@ -12,7 +12,7 @@
 /* :::::::::: menulist :::::::::: */
 
 menulist {
-  -moz-appearance: menulist;
+  appearance: menulist;
   margin: 2px 4px;
   color: -moz-DialogText;
   font: menu;
@@ -20,7 +20,7 @@ menulist {
 }
 
 .menulist-label-box {
-  -moz-appearance: menulist-text;
+  appearance: menulist-text;
   -moz-box-align: center;
   -moz-box-pack: center;
   color: inherit;
@@ -58,12 +58,12 @@ menulist[disabled="true"]:hover:active {
 /* ::::: editable menulists ::::: */
 
 menulist[editable="true"] {
-  -moz-appearance: none;
+  appearance: none;
   color: -moz-FieldText;
 }
 
 .menulist-editable-box {
-  -moz-appearance: menulist-textfield;
+  appearance: menulist-textfield;
   padding-top: 3px;
   padding-bottom: 3px;
   padding-inline-start: 2px;
@@ -72,7 +72,7 @@ menulist[editable="true"] {
 
 menulist[editable="true"] > .menulist-dropmarker {
   display: -moz-box;
-  -moz-appearance: menulist-button;
+  appearance: menulist-button;
 %if MOZ_WIDGET_GTK == 3
   min-width: 2.5em;
   min-height: 2.25em;
diff --git a/toolkit/themes/linux/global/notification.css b/toolkit/themes/linux/global/notification.css
index f1282797bb..80d6dd14e2 100644
--- a/toolkit/themes/linux/global/notification.css
+++ b/toolkit/themes/linux/global/notification.css
@@ -6,7 +6,7 @@
 
 notification {
   color: -moz-gtk-info-bar-text;
-  -moz-appearance: -moz-gtk-info-bar;
+  appearance: -moz-gtk-info-bar;
 %if MOZ_WIDGET_GTK == 2
   background-color: InfoBackground;
 %endif
@@ -16,7 +16,7 @@ notification {
 notification[type="info"] {
   color: -moz-DialogText;
   background-color: -moz-Dialog;
-  -moz-appearance: none;
+  appearance: none;
   border-top: 1px solid ThreeDShadow;
   border-bottom: 1px solid ThreeDShadow;
 }
@@ -32,7 +32,7 @@ notificationbox[notificationside="bottom"] > notification[type="info"] {
 notification[type="critical"] {
   color: white;
   background-image: linear-gradient(rgb(212,0,0), rgb(152,0,0));
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .notification-inner {
diff --git a/toolkit/themes/linux/global/numberbox.css b/toolkit/themes/linux/global/numberbox.css
index 867e0a6e88..1d9a141d87 100644
--- a/toolkit/themes/linux/global/numberbox.css
+++ b/toolkit/themes/linux/global/numberbox.css
@@ -10,7 +10,7 @@
 @namespace html url("http://www.w3.org/1999/xhtml");
 
 textbox[type="number"] {
-  -moz-appearance: none;
+  appearance: none;
   padding: 0 !important;
   border: none;
   cursor: default;
@@ -23,7 +23,7 @@ html|*.numberbox-input {
 
 .numberbox-input-box {
   -moz-box-align: center;
-  -moz-appearance: spinner-textfield;
+  appearance: spinner-textfield;
   margin-right: -1px;
   border: 2px solid;
   -moz-border-top-colors: ThreeDShadow ThreeDDarkShadow;
@@ -34,5 +34,5 @@ html|*.numberbox-input {
 }
 
 textbox[hidespinbuttons="true"] > .numberbox-input-box {
-  -moz-appearance: textfield;
+  appearance: textfield;
 }
diff --git a/toolkit/themes/linux/global/popup.css b/toolkit/themes/linux/global/popup.css
index d435fca6f4..3380e04659 100644
--- a/toolkit/themes/linux/global/popup.css
+++ b/toolkit/themes/linux/global/popup.css
@@ -8,7 +8,7 @@
 
 menupopup,
 panel {
-  -moz-appearance: menupopup;
+  appearance: menupopup;
   min-width: 1px;
   color: MenuText;
 }
@@ -16,7 +16,7 @@ panel {
 /* ::::: arrow panel ::::: */
 
 panel[type="arrow"] {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 panel[type="arrow"][side="top"],
@@ -78,7 +78,7 @@ panel[type="arrow"][side="right"] {
 /* ::::: tooltip ::::: */
 
 tooltip {
-  -moz-appearance: tooltip;
+  appearance: tooltip;
   margin-top: 21px;
   max-width: 40em;
   color: InfoText;
diff --git a/toolkit/themes/linux/global/preferences.css b/toolkit/themes/linux/global/preferences.css
index ef6a622e41..849723097f 100644
--- a/toolkit/themes/linux/global/preferences.css
+++ b/toolkit/themes/linux/global/preferences.css
@@ -37,7 +37,7 @@ prefwindow[type="child"] .prefWindow-dlgbuttons {
 }
 
 radio[pane] {
-  -moz-appearance: none;
+  appearance: none;
   min-width: 4.5em;
   margin: 0;
   padding: 3px;
@@ -45,7 +45,7 @@ radio[pane] {
 }
 
 .paneSelector {
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 8px 8px 0 8px;
   padding: 0;
 }
diff --git a/toolkit/themes/linux/global/radio.css b/toolkit/themes/linux/global/radio.css
index 5083e82f8d..a573202c6a 100644
--- a/toolkit/themes/linux/global/radio.css
+++ b/toolkit/themes/linux/global/radio.css
@@ -11,7 +11,7 @@
 /* ::::: radio ::::: */
 
 radio {
-  -moz-appearance: radio-container;
+  appearance: radio-container;
   margin: 2px 4px;
   border-left: 2px transparent;
   border-right: 2px transparent;
@@ -27,7 +27,7 @@ radio {
    mark. */
 
 .radio-spacer-box {
-  -moz-appearance: radio;
+  appearance: radio;
   -moz-box-align: center;
   margin: 2px;
   border-right: 2px solid transparent;
@@ -38,7 +38,7 @@ radio {
 }
 
 .radio-label-box {
-  -moz-appearance: radio-label;
+  appearance: radio-label;
 }
 
 .radio-icon[src] {
diff --git a/toolkit/themes/linux/global/scrollbox.css b/toolkit/themes/linux/global/scrollbox.css
index 90cbc86523..9c10413cc1 100644
--- a/toolkit/themes/linux/global/scrollbox.css
+++ b/toolkit/themes/linux/global/scrollbox.css
@@ -6,22 +6,22 @@
 
 .autorepeatbutton-up > .autorepeatbutton-icon,
 .scrollbutton-up > .toolbarbutton-icon {
-  -moz-appearance: button-arrow-up;
+  appearance: button-arrow-up;
 }
 
 .autorepeatbutton-down > .autorepeatbutton-icon,
 .scrollbutton-down > .toolbarbutton-icon {
-  -moz-appearance: button-arrow-down;
+  appearance: button-arrow-down;
 }
 
 .autorepeatbutton-up[orient="horizontal"] > .autorepeatbutton-icon,
 .scrollbutton-up[orient="horizontal"] > .toolbarbutton-icon {
-  -moz-appearance: button-arrow-previous;
+  appearance: button-arrow-previous;
 }
 
 .autorepeatbutton-down[orient="horizontal"] > .autorepeatbutton-icon,
 .scrollbutton-down[orient="horizontal"] > .toolbarbutton-icon {
-  -moz-appearance: button-arrow-next;
+  appearance: button-arrow-next;
 }
 
 :-moz-any(.scrollbutton-up, .scrollbutton-down) > .toolbarbutton-text {
diff --git a/toolkit/themes/linux/global/splitter.css b/toolkit/themes/linux/global/splitter.css
index 193539d10b..588146c482 100644
--- a/toolkit/themes/linux/global/splitter.css
+++ b/toolkit/themes/linux/global/splitter.css
@@ -11,7 +11,7 @@
 /* ::::: splitter (vertical) ::::: */
 
 splitter {
-  -moz-appearance: splitter;
+  appearance: splitter;
   -moz-box-align: center;
   -moz-box-pack: center;
   cursor: ew-resize;
diff --git a/toolkit/themes/linux/global/tabbox.css b/toolkit/themes/linux/global/tabbox.css
index e8c3741a84..dccb77acda 100644
--- a/toolkit/themes/linux/global/tabbox.css
+++ b/toolkit/themes/linux/global/tabbox.css
@@ -19,7 +19,7 @@ tabs {
 /* ::::: tabpanels ::::: */
 
 tabpanels {
-  -moz-appearance: tabpanels;
+  appearance: tabpanels;
   border: 2px solid;
   -moz-border-right-colors: ThreeDDarkShadow ThreeDShadow;
   -moz-border-bottom-colors: ThreeDDarkShadow ThreeDShadow;
@@ -34,7 +34,7 @@ tabpanels {
 
 tab {
   position: relative;
-  -moz-appearance: tab;
+  appearance: tab;
   margin-top: 2px;
   border: 2px solid;
   border-bottom: none;
diff --git a/toolkit/themes/linux/global/textbox.css b/toolkit/themes/linux/global/textbox.css
index 9e75e0cd23..f22a3cd62f 100644
--- a/toolkit/themes/linux/global/textbox.css
+++ b/toolkit/themes/linux/global/textbox.css
@@ -12,7 +12,7 @@
 /* ::::: textbox ::::: */
 
 textbox {
-  -moz-appearance: textfield;
+  appearance: textfield;
   cursor: text;
   margin: 2px 4px;
   border: 2px solid;
@@ -58,7 +58,7 @@ textbox[disabled="true"] {
 /* ::::: plain textbox ::::: */
 
 textbox.plain {
-  -moz-appearance: none !important;
+  appearance: none !important;
   background-color: transparent;
   padding: 0px !important;
   margin: 0px !important;
diff --git a/toolkit/themes/linux/global/toolbar.css b/toolkit/themes/linux/global/toolbar.css
index 1d52aeb8f1..390dc9d850 100644
--- a/toolkit/themes/linux/global/toolbar.css
+++ b/toolkit/themes/linux/global/toolbar.css
@@ -11,20 +11,20 @@
 /* ::::: toolbox ::::: */
 
 toolbox {
-  -moz-appearance: toolbox;
+  appearance: toolbox;
 }
 
 /* ::::: menubar & toolbar ::::: */
 
 toolbar {
-  -moz-appearance: toolbar;
+  appearance: toolbar;
   min-width: 1px;
   min-height: 20px;
   padding: 2px 0px;
 }
 
 menubar, toolbar[type="menubar"] {
-  -moz-appearance: menubar;
+  appearance: menubar;
   color: -moz-menubartext;
   min-width: 1px;
   min-height: 20px;
@@ -35,13 +35,13 @@ menubar, toolbar[type="menubar"] {
 %ifdef MOZ_AUSTRALIS
 menubar:-moz-lwtheme,
 toolbar:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   color: inherit;
 }
 %else
 menubar:-moz-lwtheme,
 toolbar:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   color: inherit;
   border-style: none;
 }
@@ -49,13 +49,13 @@ toolbar:-moz-lwtheme {
 
 /* in browser.xul, the menubar is inside a toolbar... */
 toolbaritem > menubar {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 /* ::::: toolbar decorations ::::: */
 
 toolbarseparator {
-  -moz-appearance: separator;
+  appearance: separator;
   margin : 0;
   border: 0;
   min-width: 2px;
diff --git a/toolkit/themes/linux/global/toolbarbutton.css b/toolkit/themes/linux/global/toolbarbutton.css
index c28d64d13c..7fbd17b66f 100644
--- a/toolkit/themes/linux/global/toolbarbutton.css
+++ b/toolkit/themes/linux/global/toolbarbutton.css
@@ -11,7 +11,7 @@
 /* ::::: toolbarbutton ::::: */
 
 toolbarbutton {
-  -moz-appearance: toolbarbutton;
+  appearance: toolbarbutton;
   -moz-box-align: center;
   -moz-box-pack: center;
   margin: 0;
@@ -70,7 +70,7 @@ toolbarbutton:-moz-lwtheme:not(:hover):not([checked="true"]):not([open="true"]):
 /* ::::: toolbarbutton menu ::::: */
 
 .toolbarbutton-menu-dropmarker {
-  -moz-appearance: toolbarbutton-dropdown !important;
+  appearance: toolbarbutton-dropdown !important;
   list-style-image: none;
   -moz-image-region: auto;
   padding: 0;
@@ -85,7 +85,7 @@ toolbarbutton:-moz-lwtheme:not(:hover):not([checked="true"]):not([open="true"]):
 
 toolbarbutton[type="menu-button"] {
   -moz-box-align: stretch;
-  -moz-appearance: dualbutton;
+  appearance: dualbutton;
   -moz-box-orient: horizontal !important;
 }
 
@@ -132,7 +132,7 @@ toolbarbutton[type="menu-button"][disabled="true"]:hover:active {
 
 .toolbarbutton-menubutton-dropmarker {
   margin: 0 3px;
-  -moz-appearance: toolbarbutton-dropdown !important;
+  appearance: toolbarbutton-dropdown !important;
   list-style-image: none;
   -moz-image-region: auto;
 }
diff --git a/toolkit/themes/linux/global/tree.css b/toolkit/themes/linux/global/tree.css
index 2fb50da712..64f71bf389 100644
--- a/toolkit/themes/linux/global/tree.css
+++ b/toolkit/themes/linux/global/tree.css
@@ -19,7 +19,7 @@ tree {
   -moz-border-left-colors: ThreeDShadow ThreeDDarkShadow;
   background-color: -moz-Field;
   color: -moz-FieldText;
-  -moz-appearance: listbox;
+  appearance: listbox;
 }
 
 /* ::::: tree focusring ::::: */
@@ -201,7 +201,7 @@ treechildren::-moz-tree-cell-text(progressmeter) {
 
 treecol,
 treecolpicker {
-  -moz-appearance: treeheadercell;
+  appearance: treeheadercell;
   -moz-box-align: center;
   -moz-box-pack: center;
   border: 2px solid;
@@ -228,7 +228,7 @@ treecolpicker:hover {
 }
 
 treecol[hideheader="true"] {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   padding: 0;
 }
@@ -290,7 +290,7 @@ treechildren::-moz-tree-column(insertafter) {
 /* ::::: sort direction indicator :::::  */
 
 .treecol-sortdirection {
-  -moz-appearance: treeheadersortarrow;
+  appearance: treeheadersortarrow;
 }
 
 /* ::::: column picker :::::  */
@@ -302,7 +302,7 @@ treechildren::-moz-tree-column(insertafter) {
 /* ::::: twisty :::::  */
 
 treechildren::-moz-tree-twisty {
-  -moz-appearance: treetwisty;
+  appearance: treetwisty;
   padding-inline-end: 4px;
   padding-top: 1px;
   width: 9px; /* The image's width is 9 pixels */
@@ -310,7 +310,7 @@ treechildren::-moz-tree-twisty {
 }
 
 treechildren::-moz-tree-twisty(open) {
-  -moz-appearance: treetwistyopen;
+  appearance: treetwistyopen;
   width: 9px; /* The image's width is 9 pixels */
   list-style-image: url("chrome://global/skin/tree/twisty-open.png");
 }
@@ -353,7 +353,7 @@ treechildren::-moz-tree-cell-text(active, selected, editing) {
 }
 
 .tree-input {
-  -moz-appearance: none;
+  appearance: none;
   border: 1px solid Highlight;
   -moz-border-top-colors: Highlight;
   -moz-border-bottom-colors: Highlight;
diff --git a/toolkit/themes/linux/mozapps/downloads/downloads.css b/toolkit/themes/linux/mozapps/downloads/downloads.css
index bb441f4b11..e3440ac9cc 100644
--- a/toolkit/themes/linux/mozapps/downloads/downloads.css
+++ b/toolkit/themes/linux/mozapps/downloads/downloads.css
@@ -8,7 +8,7 @@
 
 /* Download View */
 #downloadView {
-  -moz-appearance: none !important;
+  appearance: none !important;
   margin: 0;
   border-bottom: 2px solid;
   -moz-border-bottom-colors: ThreeDHighlight ThreeDLightShadow;
@@ -33,7 +33,7 @@ richlistitem[type="download"] .dateTime {
 }
 
 .mini-button {
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   border: none;
   padding: 0;
diff --git a/toolkit/themes/linux/mozapps/extensions/extensions.css b/toolkit/themes/linux/mozapps/extensions/extensions.css
index 577c65e654..b3259fb65d 100644
--- a/toolkit/themes/linux/mozapps/extensions/extensions.css
+++ b/toolkit/themes/linux/mozapps/extensions/extensions.css
@@ -116,7 +116,7 @@
 /*** category selector ***/
 
 #categories {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   -moz-margin-end: -1px;
   background-color: transparent;
@@ -125,7 +125,7 @@
 }
 
 .category {
-  -moz-appearance: none;
+  appearance: none;
   border-width: 1px;
   -moz-border-end-width: 0;
   border-style: solid;
@@ -310,7 +310,7 @@
 /*** sorters ***/
 
 .sort-controls {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .sorter[checkState="1"] .button-icon {
@@ -361,7 +361,7 @@
 /*** list ***/
 
 .list {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0;
   border: none;
   background-color: transparent;
@@ -555,7 +555,7 @@
 }
 
 .addon .relnotes-toggle {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background: transparent;
   font-weight: bold;
@@ -821,7 +821,7 @@ setting[type="radio"] > radiogroup {
 }
 
 .download-progress .cancel {
-  -moz-appearance: none;
+  appearance: none;
   background-color: ButtonFace;
   padding-bottom: 1px;
   -moz-padding-start: 2px;
@@ -903,7 +903,7 @@ setting[type="radio"] > radiogroup {
 }
 
 .button-link {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   border: none;
   text-decoration: underline;
diff --git a/toolkit/themes/linux/mozapps/extensions/selectAddons.css b/toolkit/themes/linux/mozapps/extensions/selectAddons.css
index 8a94a6c185..eecd9f5019 100644
--- a/toolkit/themes/linux/mozapps/extensions/selectAddons.css
+++ b/toolkit/themes/linux/mozapps/extensions/selectAddons.css
@@ -69,7 +69,7 @@
 }
 
 #select-header .select-cell {
-  -moz-appearance: treeheadercell;
+  appearance: treeheadercell;
   box-sizing: border-box;
 }
 
diff --git a/toolkit/themes/linux/mozapps/update/updates.css b/toolkit/themes/linux/mozapps/update/updates.css
index 90ff4f511b..9b97a0c37e 100644
--- a/toolkit/themes/linux/mozapps/update/updates.css
+++ b/toolkit/themes/linux/mozapps/update/updates.css
@@ -61,7 +61,7 @@ wizardpage {
 
 #pauseButton {
   list-style-image: url("moz-icon://stock/gtk-media-pause?size=menu");
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   border: none;
   min-width: 0;
@@ -120,7 +120,7 @@ update {
 }
 
 #historyItems {
-  -moz-appearance: listbox;
+  appearance: listbox;
   height: 200px;
   margin: 1px 5px 4px 5px;
 }
diff --git a/toolkit/themes/osx/global/alerts/alert.css b/toolkit/themes/osx/global/alerts/alert.css
index 3ca1a6e066..669312d1e4 100644
--- a/toolkit/themes/osx/global/alerts/alert.css
+++ b/toolkit/themes/osx/global/alerts/alert.css
@@ -11,7 +11,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 #alertNotification {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
 }
 
@@ -23,7 +23,7 @@
 }
 
 .alertCloseButton {
-  -moz-appearance: none;
+  appearance: none;
   padding: 0;
   margin: 2px;
   border: none;
diff --git a/toolkit/themes/osx/global/autocomplete.css b/toolkit/themes/osx/global/autocomplete.css
index 7e05d2f29c..bff15a3279 100644
--- a/toolkit/themes/osx/global/autocomplete.css
+++ b/toolkit/themes/osx/global/autocomplete.css
@@ -26,7 +26,7 @@ textbox:not(.padded) .textbox-input-box {
 /* ::::: history button ::::: */
 
 .autocomplete-history-dropmarker {
-  -moz-appearance: none !important;
+  appearance: none !important;
   border: none !important;
   background-color: transparent !important;
   padding: 0px;
@@ -43,7 +43,7 @@ panel[type="autocomplete-richlistbox"],
   color: -moz-FieldText;
   background-color: -moz-Field;
   font: icon;
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .autocomplete-history-popup {
@@ -53,13 +53,13 @@ panel[type="autocomplete-richlistbox"],
 /* ::::: tree ::::: */
 
 .autocomplete-tree {
-  -moz-appearance: none !important;
+  appearance: none !important;
   border: none !important;
   background-color: transparent !important;
 }
 
 .autocomplete-treecol {
-  -moz-appearance: none !important;
+  appearance: none !important;
   margin: 0 !important;
   border: none !important;
   padding: 0 !important;
@@ -89,7 +89,7 @@ treechildren.autocomplete-treebody::-moz-tree-cell-text(selected) {
 /* ::::: richlistbox autocomplete ::::: */
 
 .autocomplete-richlistbox {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0;
 }
 
diff --git a/toolkit/themes/osx/global/button.css b/toolkit/themes/osx/global/button.css
index 45f292e1f1..24b60d0140 100644
--- a/toolkit/themes/osx/global/button.css
+++ b/toolkit/themes/osx/global/button.css
@@ -5,7 +5,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 button {
-  -moz-appearance: button;
+  appearance: button;
   /* The horizontal margin used here come from the Aqua Human Interface
      Guidelines, there should be 12 pixels between two buttons. */
   margin: 5px 6px 3px;
@@ -60,7 +60,7 @@ button[type="menu-button"] {
 
 .button-menu-dropmarker,
 .button-menubutton-dropmarker {
-  -moz-appearance: none !important;
+  appearance: none !important;
   border: none;
   background-color: transparent !important;
   margin: 1px;
@@ -80,6 +80,6 @@ button.plain {
 /* ::::: help button ::::: */
 
 button[dlgtype="help"] {
-  -moz-appearance: -moz-mac-help-button;
+  appearance: -moz-mac-help-button;
   width: 20px;
 }
diff --git a/toolkit/themes/osx/global/checkbox.css b/toolkit/themes/osx/global/checkbox.css
index b49af98d04..139f71347a 100644
--- a/toolkit/themes/osx/global/checkbox.css
+++ b/toolkit/themes/osx/global/checkbox.css
@@ -5,7 +5,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 checkbox {
-  -moz-appearance: checkbox-container;
+  appearance: checkbox-container;
   -moz-box-align: center;
   margin: 4px 2px;
 }
@@ -27,7 +27,7 @@ checkbox[disabled="true"] {
 /* ::::: checkmark image ::::: */
 
 .checkbox-check {
-  -moz-appearance: checkbox;
+  appearance: checkbox;
   margin: 1px 1px 0;
   /* vertical-align tells native theming where to snap to. However, this doesn't
    * always work reliably because of bug 503833. */
diff --git a/toolkit/themes/osx/global/colorpicker.css b/toolkit/themes/osx/global/colorpicker.css
index 075437db89..ec32e21f02 100644
--- a/toolkit/themes/osx/global/colorpicker.css
+++ b/toolkit/themes/osx/global/colorpicker.css
@@ -12,7 +12,7 @@ colorpicker[type="button"] {
   border: 1px solid #a7a7a7;
   background-color: ThreeDFace;
   padding: 3px;
-  -moz-appearance: button-bevel;
+  appearance: button-bevel;
 }
 
 .colorpicker-button-colorbox {
diff --git a/toolkit/themes/osx/global/console/console.css b/toolkit/themes/osx/global/console/console.css
index f18f6f680c..c328f11ed4 100644
--- a/toolkit/themes/osx/global/console/console.css
+++ b/toolkit/themes/osx/global/console/console.css
@@ -108,7 +108,7 @@
 /* ::::: toolbars ::::: */
 
 #ToolbarEval {
-  -moz-appearance: none;
+  appearance: none;
   background: @scopeBarBackground@;
   border-bottom: @scopeBarSeparatorBorder@;
   padding: 2px;
@@ -126,7 +126,7 @@
 #ButtonEval {
   margin: 0 4px;
   padding: 1px 10px;
-  -moz-appearance: none;
+  appearance: none;
   border-radius: 10000px;
   border: @roundButtonBorder@;
   background: @roundButtonBackground@;
@@ -157,7 +157,7 @@ toolbarseparator {
 #Console\:clear {
   -moz-box-orient: vertical;
   -moz-box-align: center;
-  -moz-appearance: toolbarbutton;
+  appearance: toolbarbutton;
   font: menu;
   text-shadow: @loweredShadow@;
   margin: 4px 0 9px;
diff --git a/toolkit/themes/osx/global/customizeToolbar.css b/toolkit/themes/osx/global/customizeToolbar.css
index bcedb2b99a..3615ca3022 100644
--- a/toolkit/themes/osx/global/customizeToolbar.css
+++ b/toolkit/themes/osx/global/customizeToolbar.css
@@ -4,7 +4,7 @@
 
 #palette-box {
   margin-top: 2px;
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 0 0 10px;
 }
 
@@ -18,7 +18,7 @@
 }
 
 #main-box > separator {
-  -moz-appearance: none;
+  appearance: none;
   border-bottom: none;
 } 
 
diff --git a/toolkit/themes/osx/global/datetimepicker.css b/toolkit/themes/osx/global/datetimepicker.css
index 3d7b201f2e..5d6e5faec5 100644
--- a/toolkit/themes/osx/global/datetimepicker.css
+++ b/toolkit/themes/osx/global/datetimepicker.css
@@ -12,7 +12,7 @@ datepicker, timepicker {
 }
 
 .datetimepicker-input-box {
-  -moz-appearance: textfield;
+  appearance: textfield;
   cursor: text;
   margin-right: 4px;
   margin-bottom: 2px;
@@ -96,7 +96,7 @@ timepicker[disabled="true"] {
 }
 
 .datepicker-button {
-  -moz-appearance: none;
+  appearance: none;
   min-width: 8px;
   padding: 0px;
 }
diff --git a/toolkit/themes/osx/global/dialog.css b/toolkit/themes/osx/global/dialog.css
index 98ed3ca207..3d05c7a597 100644
--- a/toolkit/themes/osx/global/dialog.css
+++ b/toolkit/themes/osx/global/dialog.css
@@ -13,7 +13,7 @@
 }
 
 dialog { 
-  -moz-appearance: dialog;
+  appearance: dialog;
   padding: 14px;
 }
 
diff --git a/toolkit/themes/osx/global/dropmarker.css b/toolkit/themes/osx/global/dropmarker.css
index 701eea75c4..fa265305d7 100644
--- a/toolkit/themes/osx/global/dropmarker.css
+++ b/toolkit/themes/osx/global/dropmarker.css
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 dropmarker {
-  -moz-appearance: menulist-button;
+  appearance: menulist-button;
   width: 16px;
   -moz-box-align: center;
   -moz-box-pack: center;
diff --git a/toolkit/themes/osx/global/filefield.css b/toolkit/themes/osx/global/filefield.css
index 8ae3fdb52a..21abf14975 100644
--- a/toolkit/themes/osx/global/filefield.css
+++ b/toolkit/themes/osx/global/filefield.css
@@ -17,7 +17,7 @@
 filefield {
   margin: 4px;
   margin-inline-start: 27px;
-  -moz-appearance: textfield;
+  appearance: textfield;
 }
 
 .fileFieldContentBox {
@@ -31,7 +31,7 @@ filefield {
 }
 
 .fileFieldLabel {
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   border: none;
   margin: 0 4px;
diff --git a/toolkit/themes/osx/global/findBar.css b/toolkit/themes/osx/global/findBar.css
index 869a624322..68c675b88a 100644
--- a/toolkit/themes/osx/global/findBar.css
+++ b/toolkit/themes/osx/global/findBar.css
@@ -25,7 +25,7 @@ findbar[hidden] {
 }
 
 findbar:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   background: none;
   border-style: none;
 }
@@ -68,7 +68,7 @@ label.findbar-find-fast:-moz-lwtheme,
 .findbar-highlight {
   margin: 0 4px;
   padding: 1px 3px;
-  -moz-appearance: none;
+  appearance: none;
   border-radius: 10000px;
   border: @roundButtonBorder@;
   background: @roundButtonBackground@;
@@ -112,7 +112,7 @@ label.findbar-find-fast:-moz-lwtheme,
 .findbar-container > checkbox {
   list-style-image: url("chrome://global/skin/icons/checkbox.png");
   -moz-image-region: rect(0px 16px 16px 0px);
-  -moz-appearance: none;
+  appearance: none;
   margin: 0 2px;
   -moz-margin-start: 7px;
 }
@@ -174,7 +174,7 @@ label.findbar-find-fast:-moz-lwtheme,
 /* Search field */
 
 .findbar-textbox {
-  -moz-appearance: none;
+  appearance: none;
   border-radius: 10000px;
   border: none;
   box-shadow: 0 1px 1.5px rgba(0, 0, 0, .7) inset,
diff --git a/toolkit/themes/osx/global/global.css b/toolkit/themes/osx/global/global.css
index 261abe3138..914cd74e95 100644
--- a/toolkit/themes/osx/global/global.css
+++ b/toolkit/themes/osx/global/global.css
@@ -30,7 +30,7 @@ page,
 dialog,
 wizard,
 prefwindow { 
-  -moz-appearance: dialog;
+  appearance: dialog;
   background-color: #FFFFFF;
   color: -moz-DialogText;
   font: message-box;
@@ -99,7 +99,7 @@ statusbar {
   margin: 0px !important;
   /* need to use padding-inline-end when/if bug 631729 gets fixed: */
   padding: 0px 16px 1px 1px;
-  -moz-appearance: statusbar;
+  appearance: statusbar;
   text-shadow: rgba(255, 255, 255, 0.4) 0 1px;
 }
 
@@ -117,7 +117,7 @@ statusbarpanel {
 
 :root:-moz-lwtheme,
 [lwthemefooter="true"] {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 :root:-moz-lwtheme-darktext {
@@ -129,7 +129,7 @@ statusbarpanel {
 }
 
 statusbar:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   background: none;
   border-style: none;
   text-shadow: inherit;
@@ -176,7 +176,7 @@ separator.groove[orient="vertical"] {
 }
     
 .plain {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0 !important;
   border: none;
   padding: 0;
@@ -249,7 +249,7 @@ notification > button {
   padding: 1px 10px;
   min-width: 60px;
   min-height: 16px;
-  -moz-appearance: none;
+  appearance: none;
   border-radius: 10000px;
   border: @roundButtonBorder@;
   text-shadow: @loweredShadow@;
@@ -289,7 +289,7 @@ popupnotificationcontent {
   background-image: url("chrome://global/skin/icons/autoscroll.png");
   background-color: transparent;
   background-position: right top;
-  -moz-appearance: none;
+  appearance: none;
   -moz-window-shadow: none;
 }
 
@@ -316,7 +316,7 @@ popupnotificationcontent {
    * clears everything under it.
    * Without help from native theming this effect wouldn't be achievable.
    */
-  -moz-appearance: menuitem;
+  appearance: menuitem;
 }
 
 .popup-internal-box > .autorepeatbutton-up {
@@ -325,7 +325,7 @@ popupnotificationcontent {
 }
 
 .popup-internal-box > .autorepeatbutton-up > .autorepeatbutton-icon {
-  -moz-appearance: button-arrow-up;
+  appearance: button-arrow-up;
 }
 
 .popup-internal-box > .autorepeatbutton-down {
@@ -334,7 +334,7 @@ popupnotificationcontent {
 }
 
 .popup-internal-box > .autorepeatbutton-down > .autorepeatbutton-icon {
-  -moz-appearance: button-arrow-down;
+  appearance: button-arrow-down;
 }
 
 .popup-internal-box > autorepeatbutton[disabled="true"] {
diff --git a/toolkit/themes/osx/global/groupbox.css b/toolkit/themes/osx/global/groupbox.css
index 8406458278..6b9b965ce5 100644
--- a/toolkit/themes/osx/global/groupbox.css
+++ b/toolkit/themes/osx/global/groupbox.css
@@ -11,7 +11,7 @@ groupbox {
 }
 
 .groupbox-body {
-  -moz-appearance: groupbox;
+  appearance: groupbox;
   padding: 8px 8px 3px;
   margin: 0;
 }
diff --git a/toolkit/themes/osx/global/in-content/common.css b/toolkit/themes/osx/global/in-content/common.css
index a987cbfe1f..725e6aeb95 100644
--- a/toolkit/themes/osx/global/in-content/common.css
+++ b/toolkit/themes/osx/global/in-content/common.css
@@ -67,7 +67,7 @@ xul|*.radio-icon {
 }
 
 xul|*.numberbox-input-box {
-  -moz-appearance: none;
+  appearance: none;
   border-width: 0;
 }
 
@@ -98,7 +98,7 @@ xul|radio[focused="true"] > .radio-check {
 }
 
 xul|spinbuttons {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 xul|*.spinbuttons-up {
diff --git a/toolkit/themes/osx/global/inContentUI.css b/toolkit/themes/osx/global/inContentUI.css
index 17e2e6ae33..66345236b7 100644
--- a/toolkit/themes/osx/global/inContentUI.css
+++ b/toolkit/themes/osx/global/inContentUI.css
@@ -13,7 +13,7 @@
 
 /* Page background */
 *|*:root {
-  -moz-appearance: none;
+  appearance: none;
   padding: 18px;
   background-image: /* Texture */
                     url("chrome://global/skin/inContentUI/background-texture.png"),
@@ -45,7 +45,7 @@ html|html {
 *|button,
 menulist,
 colorpicker[type="button"] {
-  -moz-appearance: none;
+  appearance: none;
   padding: 1px 4px;
   min-width: 60px;
   border-radius: 3px;
@@ -99,7 +99,7 @@ menulist > .menulist-label-box > .menulist-label {
 }
 
 menulist > .menulist-dropmarker {
-  -moz-appearance: none;
+  appearance: none;
   display: -moz-box;
   background: transparent;
   border: none;
@@ -115,7 +115,7 @@ colorpicker[type="button"] {
 }
 
 spinbuttons {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 spinbuttons > .spinbuttons-box > .spinbuttons-button {
diff --git a/toolkit/themes/osx/global/listbox.css b/toolkit/themes/osx/global/listbox.css
index 90928c7699..b6945d6a59 100644
--- a/toolkit/themes/osx/global/listbox.css
+++ b/toolkit/themes/osx/global/listbox.css
@@ -5,7 +5,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 listbox {
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 2px 4px;
   background-color: #FFFFFF;
   color: -moz-FieldText;
@@ -37,7 +37,7 @@ listbox:focus > listitem[selected="true"] {
 /* ::::: listheader ::::: */
 
 listheader { 
-  -moz-appearance: treeheadercell;
+  appearance: treeheadercell;
   -moz-box-align: center;
   border: 2px solid;
   -moz-border-top-colors: ThreeDHighlight ThreeDLightShadow;
@@ -91,7 +91,7 @@ listheader[sortable="true"]:hover:active {
 /* ::::: listcell checkbox ::::: */
 
 .listcell-check {
-  -moz-appearance: checkbox;
+  appearance: checkbox;
   -moz-box-align: center;
   margin: 0px 2px;
   border: 1px solid -moz-DialogText;
diff --git a/toolkit/themes/osx/global/menu.css b/toolkit/themes/osx/global/menu.css
index 49ca168a64..3fbff0e994 100644
--- a/toolkit/themes/osx/global/menu.css
+++ b/toolkit/themes/osx/global/menu.css
@@ -7,7 +7,7 @@
 menu,
 menuitem,
 menucaption {
-  -moz-appearance: menuitem;
+  appearance: menuitem;
   -moz-box-align: center;
   color: MenuText;
   font: -moz-pull-down-menu;
@@ -88,13 +88,13 @@ menuitem[src] > .menu-iconic-left > .menu-iconic-icon {
 
 .menu-right {
   list-style-image: none;
-  -moz-appearance: menuarrow;
+  appearance: menuarrow;
 }
 
 /* ::::: menu/menuitems in menubar ::::: */
 
 menubar > menu {
-  -moz-appearance: none;
+  appearance: none;
   padding: 2px 5px 2px 7px;
   margin: 1px 0;
 }
@@ -105,7 +105,7 @@ menubar > menu[_moz-menuactive="true"] {
 }
 
 menubar > menu[_moz-menuactive="true"][open="true"] {
-  -moz-appearance: menuitem;
+  appearance: menuitem;
   color: -moz-mac-menutextselect;
 }
 
@@ -149,7 +149,7 @@ menulist > menupopup > menu {
 
 menulist[editable="true"] > menupopup > menuitem,
 menulist[editable="true"] > menupopup > menucaption {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 menulist[editable="true"] > menupopup > :-moz-any(menuitem, menucaption) > .menu-iconic-left {
@@ -160,7 +160,7 @@ menulist[editable="true"] > menupopup > :-moz-any(menuitem, menucaption) > .menu
 
 :not(menulist) > menupopup > menuitem[checked="true"],
 :not(menulist) > menupopup > menuitem[selected="true"] {
-  -moz-appearance: checkmenuitem;
+  appearance: checkmenuitem;
 }
 
 menulist:not([editable="true"]) > menupopup > menuitem[checked="true"]::before,
@@ -174,7 +174,7 @@ menulist:not([editable="true"]) > menupopup > menuitem[selected="true"]::before
 /* ::::: menuseparator ::::: */
 
 menuseparator {
-  -moz-appearance: menuseparator;
+  appearance: menuseparator;
   margin: 5px 0;
   padding: 1px 0;
 }
diff --git a/toolkit/themes/osx/global/menulist.css b/toolkit/themes/osx/global/menulist.css
index a4feca947e..e1705fe6a1 100644
--- a/toolkit/themes/osx/global/menulist.css
+++ b/toolkit/themes/osx/global/menulist.css
@@ -6,7 +6,7 @@
 @namespace html url("http://www.w3.org/1999/xhtml");
 
 menulist {
-  -moz-appearance: menulist;
+  appearance: menulist;
   margin: 5px 2px 3px;
   color: -moz-DialogText;
   text-shadow: none;
@@ -17,7 +17,7 @@ menulist:not([popuponly="true"]) {
 }
 
 .menulist-label-box {
-  -moz-appearance: menulist-text;
+  appearance: menulist-text;
   -moz-box-align: center;
   -moz-box-pack: center;
   margin-bottom: 1px;
@@ -52,7 +52,7 @@ menulist[disabled="true"] > .menulist-dropmarker {
 /* ::::: editable menulists ::::: */
 
 menulist[editable="true"] {
-  -moz-appearance: menulist-textfield;
+  appearance: menulist-textfield;
   margin: 4px 2px;
 }
 
diff --git a/toolkit/themes/osx/global/nativescrollbars.css b/toolkit/themes/osx/global/nativescrollbars.css
index 82ef4d2ac1..c6248e1702 100644
--- a/toolkit/themes/osx/global/nativescrollbars.css
+++ b/toolkit/themes/osx/global/nativescrollbars.css
@@ -6,7 +6,7 @@
 @namespace html url("http://www.w3.org/1999/xhtml");
 
 scrollbar {
-  -moz-appearance: scrollbar;
+  appearance: scrollbar;
   -moz-binding: url(chrome://global/content/bindings/scrollbar.xml#scrollbar);
   cursor: default;
   background-color: white;
@@ -19,7 +19,7 @@ scrollbar[root="true"] {
 
 html|select[size]:not([size="0"]):not([size="1"]) > scrollbar,
 html|select[multiple] > scrollbar {
-  -moz-appearance: scrollbar-small;
+  appearance: scrollbar-small;
 }
 
 @media all and (-moz-overlay-scrollbars) {
@@ -32,47 +32,47 @@ html|select[multiple] > scrollbar {
 /* ..... track ..... */
 
 slider {
-  -moz-appearance: scrollbartrack-horizontal;
+  appearance: scrollbartrack-horizontal;
 }
 
 slider[orient="vertical"] {
-  -moz-appearance: scrollbartrack-vertical;
+  appearance: scrollbartrack-vertical;
 }
 
 /* ..... thumb ..... */
 
 thumb {
-  -moz-appearance: scrollbarthumb-horizontal;
+  appearance: scrollbarthumb-horizontal;
 }
 
 thumb[orient="vertical"] {
-  -moz-appearance: scrollbarthumb-vertical;
+  appearance: scrollbarthumb-vertical;
 }
 
 /* ..... increment ..... */
 
 scrollbarbutton[type="increment"] {
-  -moz-appearance: scrollbarbutton-right;
+  appearance: scrollbarbutton-right;
 }
 
 scrollbar[orient="vertical"] > scrollbarbutton[type="increment"] {
-  -moz-appearance: scrollbarbutton-down;
+  appearance: scrollbarbutton-down;
 }
 
 /* ..... decrement ..... */
 
 scrollbarbutton[type="decrement"] {
-  -moz-appearance: scrollbarbutton-left;
+  appearance: scrollbarbutton-left;
 }
 
 scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"] {
-  -moz-appearance: scrollbarbutton-up;
+  appearance: scrollbarbutton-up;
 }
 
 /* ::::: square at the corner of two scrollbars ::::: */
 
 scrollcorner {
-  /* XXX -moz-appearance: scrollcorner; */
+  /* XXX appearance: scrollcorner; */
   -moz-binding: url(chrome://global/content/bindings/scrollbar.xml#scrollbar-base);
   width: 16px;
   cursor: default;
@@ -82,7 +82,7 @@ scrollcorner {
 /* ::::::::::::::::::::: MEDIA PRINT :::::::::::::::::::::: */
 @media print {
   html|div scrollbar {
-    -moz-appearance: scrollbar;
+    appearance: scrollbar;
     -moz-binding: url(chrome://global/content/bindings/scrollbar.xml#scrollbar);
     cursor: default;
   }
diff --git a/toolkit/themes/osx/global/notification.css b/toolkit/themes/osx/global/notification.css
index 6d22cf9c86..ece665dd35 100644
--- a/toolkit/themes/osx/global/notification.css
+++ b/toolkit/themes/osx/global/notification.css
@@ -71,7 +71,7 @@ notificationbox[notificationside="bottom"] > notification {
 }
 
 .messageCloseButton {
-  -moz-appearance: none;
+  appearance: none;
   padding: 0;
   margin: 0 2px;
   border: none;
@@ -127,7 +127,7 @@ notification[type="info"] .close-icon:not(:hover) {
 }
 
 .popup-notification-menubutton {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .popup-notification-menubutton:not([type="menu-button"]):-moz-focusring,
@@ -140,7 +140,7 @@ notification[type="info"] .close-icon:not(:hover) {
 .popup-notification-menubutton:not([type="menu-button"]),
 .popup-notification-menubutton > .button-menubutton-button,
 .popup-notification-menubutton > .button-menubutton-dropmarker {
-  -moz-appearance: none;
+  appearance: none;
   color: #434343;
   border-radius: 4px;
   border: 1px solid #b5b5b5;
@@ -154,7 +154,7 @@ notification[type="info"] .close-icon:not(:hover) {
 }
 
 .popup-notification-menubutton > .button-menubutton-button {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0;
   padding-top: 2px;
   padding-bottom: 2px;
diff --git a/toolkit/themes/osx/global/numberbox.css b/toolkit/themes/osx/global/numberbox.css
index e5de22d218..f96259bac8 100644
--- a/toolkit/themes/osx/global/numberbox.css
+++ b/toolkit/themes/osx/global/numberbox.css
@@ -6,7 +6,7 @@
 @namespace html url("http://www.w3.org/1999/xhtml");
 
 textbox[type="number"] {
-  -moz-appearance: none;
+  appearance: none;
   -moz-box-align: center;
   padding: 0 !important;
   border: none;
@@ -20,7 +20,7 @@ html|*.numberbox-input {
 }
 
 .numberbox-input-box {
-  -moz-appearance: textfield;
+  appearance: textfield;
   margin-right: 4px;
   border: 3px solid;
   -moz-border-top-colors: transparent #888888 #000000;
diff --git a/toolkit/themes/osx/global/popup.css b/toolkit/themes/osx/global/popup.css
index cf0266a3a6..d60ebfec04 100644
--- a/toolkit/themes/osx/global/popup.css
+++ b/toolkit/themes/osx/global/popup.css
@@ -6,7 +6,7 @@
 
 menupopup,
 panel {
-  -moz-appearance: menupopup;
+  appearance: menupopup;
   background-color: Menu;
 }
 
@@ -19,11 +19,11 @@ menupopup > menu > menupopup {
 }
 
 panel[titlebar] {
-  -moz-appearance: none; /* to disable rounded corners */
+  appearance: none; /* to disable rounded corners */
 }
 
 panel[type="arrow"] {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
 }
 
@@ -40,7 +40,7 @@ panel[type="arrow"][side="right"] {
 }
 
 .panel-arrowcontent {
-  -moz-appearance: none;
+  appearance: none;
   background: var(--arrowpanel-background);
   border-radius: var(--arrowpanel-border-radius);
   box-shadow: 0 0 0 1px var(--arrowpanel-border-color);
@@ -101,7 +101,7 @@ panel[type="arrow"][side="right"] {
 /* ::::: tooltip ::::: */
 
 tooltip {
-  -moz-appearance: tooltip;
+  appearance: tooltip;
   margin-top: 18px;
   padding: 2px 3px;
   max-width: 40em;
@@ -129,7 +129,7 @@ menulist > menupopup:not([position]) {
 }
 
 menulist[editable="true"] > menupopup {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 menulist > menupopup > .popup-internal-box {
diff --git a/toolkit/themes/osx/global/preferences.css b/toolkit/themes/osx/global/preferences.css
index d0b82a819c..0c5f9503d6 100644
--- a/toolkit/themes/osx/global/preferences.css
+++ b/toolkit/themes/osx/global/preferences.css
@@ -25,7 +25,7 @@ prefwindow[type="child"] > prefpane {
 .paneSelector {
   font: message-box;
   padding: 1px 4px;
-  -moz-appearance: toolbar;
+  appearance: toolbar;
   margin: 0;
 }
 
@@ -34,7 +34,7 @@ radio[pane] {
   border-width: 0 2px;
   padding: 5px 4px 3px;
   margin: 0;
-  -moz-appearance: none;
+  appearance: none;
   text-shadow: rgba(255, 255, 255, 0.4) 0 1px;
 }
 
diff --git a/toolkit/themes/osx/global/progressmeter.css b/toolkit/themes/osx/global/progressmeter.css
index 13fce252ab..a8556b8658 100644
--- a/toolkit/themes/osx/global/progressmeter.css
+++ b/toolkit/themes/osx/global/progressmeter.css
@@ -5,7 +5,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 progressmeter {
-  -moz-appearance: progressbar;
+  appearance: progressbar;
   margin: 2px 4px;
   min-width: 128px;
   height: 12px;
@@ -13,7 +13,7 @@ progressmeter {
 
 .progress-remainder[flex="100"], .progress-remainder[flex="0"] {
   background-image: none !important;
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .progressmeter-statusbar {
diff --git a/toolkit/themes/osx/global/radio.css b/toolkit/themes/osx/global/radio.css
index e21d93011b..13de398cff 100644
--- a/toolkit/themes/osx/global/radio.css
+++ b/toolkit/themes/osx/global/radio.css
@@ -9,7 +9,7 @@ radiogroup {
 }
 
 radio {
-  -moz-appearance: radio-container;
+  appearance: radio-container;
   -moz-box-align: center;
   margin: 4px 2px;
   -moz-user-focus: ignore;
@@ -33,7 +33,7 @@ radio[disabled="true"] {
 }
 
 .radio-check, .radio-check-box1 {
-  -moz-appearance: radio;
+  appearance: radio;
   margin: 0 1px 1px;
   /* vertical-align tells native theming where to snap to. However, this doesn't
    * always work reliably because of bug 503833. */
diff --git a/toolkit/themes/osx/global/resizer.css b/toolkit/themes/osx/global/resizer.css
index 18cdd2bc93..98de30e1f2 100644
--- a/toolkit/themes/osx/global/resizer.css
+++ b/toolkit/themes/osx/global/resizer.css
@@ -5,7 +5,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 resizer {
-  -moz-appearance: resizer;
+  appearance: resizer;
   background: url("chrome://global/skin/icons/resizer.png") no-repeat;
   background-size: 100% 100%;
   cursor: se-resize;
diff --git a/toolkit/themes/osx/global/richlistbox.css b/toolkit/themes/osx/global/richlistbox.css
index 605c89abb3..632ff4f0ca 100644
--- a/toolkit/themes/osx/global/richlistbox.css
+++ b/toolkit/themes/osx/global/richlistbox.css
@@ -5,7 +5,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 richlistbox {
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 2px 4px;
   background-color: -moz-Field;
   color: -moz-FieldText;
diff --git a/toolkit/themes/osx/global/scale.css b/toolkit/themes/osx/global/scale.css
index 2e090bf28d..ea405b1446 100644
--- a/toolkit/themes/osx/global/scale.css
+++ b/toolkit/themes/osx/global/scale.css
@@ -5,7 +5,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 .scale-slider {
-  -moz-appearance: scale-horizontal;
+  appearance: scale-horizontal;
   background: url("chrome://global/skin/scale/scale-tray-horiz.gif") 0% 50% repeat-x;
   margin: 2px 4px;
   width: 100px;
@@ -13,7 +13,7 @@
 
 .scale-slider[orient="vertical"]
 {
-  -moz-appearance: scale-vertical;
+  appearance: scale-vertical;
   background: url("chrome://global/skin/scale/scale-tray-vert.gif") 50% 0% repeat-y;
   margin: 4px 2px;
   width: auto;
@@ -21,7 +21,7 @@
 }
 
 .scale-thumb {
-  -moz-appearance: scalethumb-horizontal;
+  appearance: scalethumb-horizontal;
   border: 2px solid;
   -moz-border-top-colors: ThreeDLightShadow ThreeDHighlight;
   -moz-border-right-colors: ThreeDDarkShadow ThreeDShadow;
@@ -33,7 +33,7 @@
 }
 
 .scale-thumb[orient="vertical"] {
-  -moz-appearance: scalethumb-vertical;
+  appearance: scalethumb-vertical;
   min-width: 15px;
   min-height: 30px;
 }
diff --git a/toolkit/themes/osx/global/spinbuttons.css b/toolkit/themes/osx/global/spinbuttons.css
index bf89520f68..d48cf41e5a 100644
--- a/toolkit/themes/osx/global/spinbuttons.css
+++ b/toolkit/themes/osx/global/spinbuttons.css
@@ -7,12 +7,12 @@
 spinbuttons {
   height: 24px;
   min-height: 24px;
-  -moz-appearance: spinner;
+  appearance: spinner;
   cursor: default;
 }
 
 .spinbuttons-up {
-  -moz-appearance: none;
+  appearance: none;
   -moz-box-flex: 1;
   min-width: 1px;
   min-height: 1px;
@@ -21,7 +21,7 @@ spinbuttons {
 }
 
 .spinbuttons-down {
-  -moz-appearance: none;
+  appearance: none;
   -moz-box-flex: 1;
   min-width: 1px;
   min-height: 1px;
diff --git a/toolkit/themes/osx/global/tabbox.css b/toolkit/themes/osx/global/tabbox.css
index 4fcbac486d..68b4ec5650 100644
--- a/toolkit/themes/osx/global/tabbox.css
+++ b/toolkit/themes/osx/global/tabbox.css
@@ -18,7 +18,7 @@ tabbox {
 }
 
 tabpanels {
-  -moz-appearance: tabpanels;
+  appearance: tabpanels;
   padding: 33px 15px 15px;
 }
 
@@ -34,7 +34,7 @@ tabbox > tabs {
 }
 
 tab {
-  -moz-appearance: tab;
+  appearance: tab;
 }
 
 tab:-moz-focusring {
@@ -90,7 +90,7 @@ tabs.tabs-bottom > .tabs-left {
 
 tabbox.tabs-bottom > tabs > tab,
 tabs.tabs-bottom > tab {
-  -moz-appearance: none;
+  appearance: none;
   margin: -1px 0 0;
   padding: 0 0 2px 0;
   position: relative;
@@ -144,5 +144,5 @@ tabbox.tabs-bottom,
 tabbox.tabs-bottom > tabpanels,
 tabbox.tabs-bottom > tabs > tab[visuallyselected=true] > .tab-middle,
 tabs.tabs-bottom > tab[visuallyselected=true] > .tab-middle {
-  -moz-appearance: dialog;
+  appearance: dialog;
 }
diff --git a/toolkit/themes/osx/global/tabprompts.css b/toolkit/themes/osx/global/tabprompts.css
index 14a23f2696..37c3260a46 100644
--- a/toolkit/themes/osx/global/tabprompts.css
+++ b/toolkit/themes/osx/global/tabprompts.css
@@ -29,7 +29,7 @@ tabmodalprompt {
 }
 
 button {
-  -moz-appearance: none;
+  appearance: none;
   padding: 2px 0;
   margin: 0;
   margin-inline-start: 8px;
diff --git a/toolkit/themes/osx/global/textbox.css b/toolkit/themes/osx/global/textbox.css
index d7a31c7acc..e73d01417b 100644
--- a/toolkit/themes/osx/global/textbox.css
+++ b/toolkit/themes/osx/global/textbox.css
@@ -6,7 +6,7 @@
 @namespace html url("http://www.w3.org/1999/xhtml");
 
 textbox {
-  -moz-appearance: textfield;
+  appearance: textfield;
   cursor: text;
   margin: 4px;
   border: 3px solid;
@@ -58,7 +58,7 @@ textbox[disabled="true"] {
 } 
 
 textbox.plain {
-  -moz-appearance: none !important;
+  appearance: none !important;
   background-color: transparent;
   padding: 0px !important;
   margin: 0px !important;
@@ -73,7 +73,7 @@ textbox.plain html|*.textbox-textarea {
 /* ::::: search box ::::: */
 
 textbox[type="search"] {
-  -moz-appearance: searchfield;
+  appearance: searchfield;
   padding: 1px;
   font-size: 12px;
 }
diff --git a/toolkit/themes/osx/global/toolbar.css b/toolkit/themes/osx/global/toolbar.css
index f07332d2f3..0ab3066579 100644
--- a/toolkit/themes/osx/global/toolbar.css
+++ b/toolkit/themes/osx/global/toolbar.css
@@ -5,40 +5,40 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 toolbox {
-  /* Setting -moz-appearance:toolbox causes sheets to attach under the
+  /* Setting appearance:toolbox causes sheets to attach under the
    * toolbox and has no other effects. It doesn't render anything. */
-  -moz-appearance: toolbox;
+  appearance: toolbox;
 }
 
 toolbar {
   min-width: 1px;
   min-height: 20px;
-  -moz-appearance: toolbar;
+  appearance: toolbar;
 }
 
 %ifdef MOZ_AUSTRALIS
 menubar:-moz-lwtheme,
 toolbar:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   background: none;
   border-color: transparent;
 }
 %else
 menubar:-moz-lwtheme,
 toolbar:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   background: none;
   border-style: none;
 }
 %endif
 
 menubar {
-  -moz-appearance: dialog; /* For content menubars, "toolbar" is too dark, so we use "dialog". */
+  appearance: dialog; /* For content menubars, "toolbar" is too dark, so we use "dialog". */
   min-width: 1px;
 }
 
 toolbarseparator {
-  -moz-appearance: none;
+  appearance: none;
   margin: 3px 4px;
   background: url("chrome://global/skin/toolbar/toolbar-separator.png") transparent repeat-y;
   padding: 0;
diff --git a/toolkit/themes/osx/global/toolbarbutton.css b/toolkit/themes/osx/global/toolbarbutton.css
index ab24387e3c..ee6a4d77f5 100644
--- a/toolkit/themes/osx/global/toolbarbutton.css
+++ b/toolkit/themes/osx/global/toolbarbutton.css
@@ -35,7 +35,7 @@ toolbarbutton[disabled="true"][open="true"] {
 /* ::::: toolbarbutton menu ::::: */
 
 .toolbarbutton-menu-dropmarker {
-  -moz-appearance: none !important;
+  appearance: none !important;
   border: none !important;
   background-color: transparent !important;
   list-style-image: url("chrome://global/skin/arrow/arrow-dn.png");
@@ -107,7 +107,7 @@ toolbar[mode="icons"] > *|* > .toolbarbutton-badge {
 /* .......... dropmarker .......... */
 
 .toolbarbutton-menubutton-dropmarker {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background-color: transparent !important;
   list-style-image: url("chrome://global/skin/arrow/arrow-dn.png");
diff --git a/toolkit/themes/osx/global/tree.css b/toolkit/themes/osx/global/tree.css
index 472a51fc91..610a74e560 100644
--- a/toolkit/themes/osx/global/tree.css
+++ b/toolkit/themes/osx/global/tree.css
@@ -9,7 +9,7 @@ tree {
   margin: 0px 4px;
   color: -moz-DialogText;
   background-color: #FFFFFF;
-  -moz-appearance: listbox;
+  appearance: listbox;
 }
 
 /* ::::: tree focusring ::::: */
@@ -157,14 +157,14 @@ treechildren::-moz-tree-progressmeter {
 
 treechildren::-moz-tree-cell-text(progressmeter) {
   margin: 2px 4px;
-  -moz-appearance: progressbar;
+  appearance: progressbar;
 }
 
 /* ::::: tree columns ::::: */
 
 treecol,
 treecolpicker { 
-  -moz-appearance: treeheadercell;
+  appearance: treeheadercell;
   -moz-box-align: center;
   -moz-box-pack: center;
   border: 2px solid;
@@ -186,7 +186,7 @@ treecolpicker {
 }
 
 treecol[hideheader="true"] {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   padding: 0;
   max-height: 0px;
@@ -246,16 +246,16 @@ treechildren::-moz-tree-column(insertafter) {
 /* ::::: twisty :::::  */
 
 treechildren::-moz-tree-twisty {
-  -moz-appearance: treetwisty;
+  appearance: treetwisty;
   padding-inline-end: 2px;
 }
 
 treechildren::-moz-tree-twisty(open) {
-  -moz-appearance: treetwistyopen;
+  appearance: treetwistyopen;
 }
 
 treechildren::-moz-tree-twisty(Name, separator) {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 treechildren::-moz-tree-indentation {
@@ -276,7 +276,7 @@ treechildren.gridlines::-moz-tree-row {
 /* ::::: editable tree ::::: */
 
 .tree-input {
-  -moz-appearance: none;
+  appearance: none;
   border-width: 0;
   box-shadow: @focusRingShadow@;
   margin: 0;
diff --git a/toolkit/themes/osx/global/viewbuttons.css b/toolkit/themes/osx/global/viewbuttons.css
index bb407a64ed..44c521c88b 100644
--- a/toolkit/themes/osx/global/viewbuttons.css
+++ b/toolkit/themes/osx/global/viewbuttons.css
@@ -5,7 +5,7 @@
 %include shared.inc
 
 #topBar {
-  -moz-appearance: toolbar;
+  appearance: toolbar;
 }
 
 .viewGroupWrapper {
@@ -21,7 +21,7 @@
 #viewGroup > toolbarbutton {
   -moz-box-orient: vertical;
   -moz-box-align: center;
-  -moz-appearance: toolbarbutton;
+  appearance: toolbarbutton;
   font: menu;
   text-shadow: @loweredShadow@;
   margin: 0;
diff --git a/toolkit/themes/osx/global/wizard.css b/toolkit/themes/osx/global/wizard.css
index 9c5e6200ce..f8ce18c947 100644
--- a/toolkit/themes/osx/global/wizard.css
+++ b/toolkit/themes/osx/global/wizard.css
@@ -13,7 +13,7 @@ wizard {
 }
 
 .wizard-header {
-  -moz-appearance: dialog;
+  appearance: dialog;
 }
 
 .wizard-header-box-1 {
@@ -44,7 +44,7 @@ wizard[branded="true"] .wizard-header-icon {
 
 .wizard-page-box {
   padding: 15px 23px;
-  -moz-appearance: dialog;
+  appearance: dialog;
 }
 
 .wizard-buttons-separator {
diff --git a/toolkit/themes/osx/mozapps/downloads/downloads.css b/toolkit/themes/osx/mozapps/downloads/downloads.css
index 3ba246c1fc..16f3b55f1a 100644
--- a/toolkit/themes/osx/mozapps/downloads/downloads.css
+++ b/toolkit/themes/osx/mozapps/downloads/downloads.css
@@ -5,7 +5,7 @@
 %include ../../global/shared.inc
 
 #downloadView {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0;
   padding: 0;
   border-width: 0;
@@ -39,7 +39,7 @@ richlistbox:focus > richlistitem[selected="true"][type="download"] .status {
 
 
 richlistitem[type="download"] button {
-  -moz-appearance: none;
+  appearance: none;
   min-height: 16px;
   min-width: 16px;
   max-height: 16px;
@@ -111,11 +111,11 @@ richlistitem[type="download"] button {
 #search {
   -moz-box-pack: end;
   padding-inline-end: 4px;
-  -moz-appearance: statusbar;
+  appearance: statusbar;
 }
 
 #clearListButton {
-  -moz-appearance: toolbarbutton;
+  appearance: toolbarbutton;
   min-height: 18px;
   min-width: 0;
   margin: 0 6px;
diff --git a/toolkit/themes/osx/mozapps/extensions/eula.css b/toolkit/themes/osx/mozapps/extensions/eula.css
index 5fb2c52df2..a8754994c2 100644
--- a/toolkit/themes/osx/mozapps/extensions/eula.css
+++ b/toolkit/themes/osx/mozapps/extensions/eula.css
@@ -34,7 +34,7 @@
 }
 
 #eula {
-  -moz-appearance: none;
+  appearance: none;
   color: -moz-FieldText;
   background-color: -moz-Field;
   margin: 1em;
diff --git a/toolkit/themes/osx/mozapps/extensions/extensions.css b/toolkit/themes/osx/mozapps/extensions/extensions.css
index 80ca44c191..8bd3f64cee 100644
--- a/toolkit/themes/osx/mozapps/extensions/extensions.css
+++ b/toolkit/themes/osx/mozapps/extensions/extensions.css
@@ -148,7 +148,7 @@
 /*** category selector ***/
 
 #categories {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   -moz-margin-end: -1px;
   background-color: transparent;
@@ -157,7 +157,7 @@
 }
 
 .category {
-  -moz-appearance: none;
+  appearance: none;
   color: #252F3B;
   border-width: 1px;
   border-style: solid;
@@ -306,7 +306,7 @@
 
 #header-search {
   margin: 0;
-  -moz-appearance: none;
+  appearance: none;
   padding: 3px 5px 2px;
   border: 1px solid rgba(60,73,97,0.5);
   border-radius: 10000px;
@@ -352,11 +352,11 @@
 /*** sorters ***/
 
 .sort-controls {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .sorter {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   color: #41434B;
   background-color: transparent;
@@ -430,7 +430,7 @@
 /*** list ***/
 
 .list {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0;
   border: none;
   background-color: transparent;
@@ -617,7 +617,7 @@
 }
 
 .addon .relnotes-toggle {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background: transparent;
   font-weight: bold;
@@ -712,7 +712,7 @@
 }
 
 .search-filter-radio {
-  -moz-appearance: none;
+  appearance: none;
   padding: 0 10px;
   margin: 0 3px;
   border-radius: 10000px;
@@ -845,7 +845,7 @@
 }
 
 #detail-contrib-btn {
-  -moz-appearance: none;
+  appearance: none;
   color: #FFF;
   border: 1px solid #3A4EEE;
   border-radius: 3px;
@@ -1001,7 +1001,7 @@ setting[type="radio"] > radiogroup {
 .download-progress[complete] .end-cap,
 .download-progress[mode="undetermined"] .end-cap,
 .download-progress .progress .progress-bar {
-  -moz-appearance: none;
+  appearance: none;
   background-image: linear-gradient(#6AC47E, #4FAC6A);
   margin-top: -1px;
   margin-bottom: -1px;
@@ -1025,7 +1025,7 @@ setting[type="radio"] > radiogroup {
 }
 
 .download-progress .progress {
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   padding: 0;
   margin: 0;
@@ -1048,7 +1048,7 @@ setting[type="radio"] > radiogroup {
 }
 
 .download-progress .cancel {
-  -moz-appearance: none;
+  appearance: none;
   background-color: rgba(255, 255, 255, 0.15);
   border: 1px solid rgba(0, 0, 0, 0.4);
   padding: 3px;
@@ -1117,7 +1117,7 @@ setting[type="radio"] > radiogroup {
 }
 
 button.button-link {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   border: none;
   box-shadow: none;
@@ -1145,7 +1145,7 @@ button.button-link:not([disabled="true"]):active:hover {
 }
 
 .header-button {
-  -moz-appearance: none;
+  appearance: none;
   padding: 0 4px;
   margin: 0;
   height: 22px;
diff --git a/toolkit/themes/osx/mozapps/extensions/selectAddons.css b/toolkit/themes/osx/mozapps/extensions/selectAddons.css
index 8682b04b51..4719df0eca 100644
--- a/toolkit/themes/osx/mozapps/extensions/selectAddons.css
+++ b/toolkit/themes/osx/mozapps/extensions/selectAddons.css
@@ -73,7 +73,7 @@
 }
 
 #select-header .select-cell {
-  -moz-appearance: treeheadercell;
+  appearance: treeheadercell;
   border: 2px solid;
   -moz-border-top-colors: ThreeDHighlight ThreeDLightShadow;
   -moz-border-right-colors: ThreeDDarkShadow ThreeDShadow;
@@ -150,12 +150,12 @@
 
 #footer {
   padding: 15px 12px;
-  -moz-appearance: statusbar;
+  appearance: statusbar;
   -moz-window-dragging: drag;
 }
 
 button {
-  -moz-appearance: toolbarbutton;
+  appearance: toolbarbutton;
   min-height: 22px;
   margin: 0 6px;
   padding: 0;
diff --git a/toolkit/themes/osx/mozapps/extensions/xpinstallConfirm.css b/toolkit/themes/osx/mozapps/extensions/xpinstallConfirm.css
index 0a1a84b249..28442f7baf 100644
--- a/toolkit/themes/osx/mozapps/extensions/xpinstallConfirm.css
+++ b/toolkit/themes/osx/mozapps/extensions/xpinstallConfirm.css
@@ -17,7 +17,7 @@
 }
 
 #itemList {
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 3px 4px 10px 4px;
   height: 14em;
 }
@@ -58,7 +58,7 @@ installitem {
 }
 
 .xpinstallItemURL {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background-color: Window;
   margin-top: 2px;
diff --git a/toolkit/themes/osx/mozapps/update/updates.css b/toolkit/themes/osx/mozapps/update/updates.css
index 9bd78ef6f8..2133ddde67 100644
--- a/toolkit/themes/osx/mozapps/update/updates.css
+++ b/toolkit/themes/osx/mozapps/update/updates.css
@@ -34,12 +34,12 @@ wizardpage {
 /* Don't use top margin - it can cause a scrollbar on some pages */
 .wizard-buttons {
   padding: 0;
-  -moz-appearance: statusbar;
+  appearance: statusbar;
   -moz-window-dragging: drag;
 }
 
 .wizard-buttons button {
-  -moz-appearance: toolbarbutton;
+  appearance: toolbarbutton;
   color: ButtonText;
   min-height: 22px;
   margin: 0 6px;
@@ -88,7 +88,7 @@ wizardpage {
 #pauseButton {
   list-style-image: url(chrome://mozapps/skin/update/buttons.png);
   -moz-image-region: rect(48px, 16px, 64px, 0px);
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   border: none;
   min-height: 16px;
@@ -161,7 +161,7 @@ update {
 }
 
 #historyItems {
-  -moz-appearance: listbox;
+  appearance: listbox;
   height: 200px;
   margin: 1px 5px 4px 5px;
 }
diff --git a/toolkit/themes/osx/reftests/482681-ref.xul b/toolkit/themes/osx/reftests/482681-ref.xul
index 62fb4bb8d5..6fe45597cf 100644
--- a/toolkit/themes/osx/reftests/482681-ref.xul
+++ b/toolkit/themes/osx/reftests/482681-ref.xul
@@ -3,7 +3,7 @@
 <?xml-stylesheet href="data:text/css,
 vbox { height: 50px; }
 box {
-  -moz-appearance: button;
+  appearance: button;
 }
 " type="text/css"?>
 
diff --git a/toolkit/themes/osx/reftests/baseline.xul b/toolkit/themes/osx/reftests/baseline.xul
index 2ec6f5132f..87c1d919cb 100644
--- a/toolkit/themes/osx/reftests/baseline.xul
+++ b/toolkit/themes/osx/reftests/baseline.xul
@@ -46,7 +46,7 @@
 
 <html:style><![CDATA[
 window {
-  -moz-appearance: none;
+  appearance: none;
   background-color: white;
 }
 .regular {
diff --git a/toolkit/themes/osx/reftests/checkboxsize-ref.xul b/toolkit/themes/osx/reftests/checkboxsize-ref.xul
index 08d1e9a670..80bbbfd98b 100644
--- a/toolkit/themes/osx/reftests/checkboxsize-ref.xul
+++ b/toolkit/themes/osx/reftests/checkboxsize-ref.xul
@@ -3,7 +3,7 @@
 <?xml-stylesheet href="data:text/css,
 vbox { height: 50px; }
 box {
-  -moz-appearance: checkbox;
+  appearance: checkbox;
   margin-left: 2px;
   margin-top: 1px;
 }
diff --git a/toolkit/themes/osx/reftests/radiosize-ref.xul b/toolkit/themes/osx/reftests/radiosize-ref.xul
index 632f39e41f..20c9bc3a8c 100644
--- a/toolkit/themes/osx/reftests/radiosize-ref.xul
+++ b/toolkit/themes/osx/reftests/radiosize-ref.xul
@@ -3,7 +3,7 @@
 <?xml-stylesheet href="data:text/css,
 vbox { height: 50px; }
 box {
-  -moz-appearance: radio;
+  appearance: radio;
   margin-left: 2px;
   margin-top: 1px;
 }
diff --git a/toolkit/themes/shared/alert-common.css b/toolkit/themes/shared/alert-common.css
index 17510c0dbd..c3b1991b73 100644
--- a/toolkit/themes/shared/alert-common.css
+++ b/toolkit/themes/shared/alert-common.css
@@ -125,7 +125,7 @@
 }
 
 #alertSettings {
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   border-width: 0;
   border-radius: 20px;
diff --git a/toolkit/themes/shared/datetimeinputpickers.css b/toolkit/themes/shared/datetimeinputpickers.css
index 05f4ad2e77..bc32cf45e0 100644
--- a/toolkit/themes/shared/datetimeinputpickers.css
+++ b/toolkit/themes/shared/datetimeinputpickers.css
@@ -58,7 +58,7 @@ body {
 }
 
 button {
-  -moz-appearance: none;
+  appearance: none;
   background: none;
   border: none;
 }
diff --git a/toolkit/themes/shared/in-content/common.inc.css b/toolkit/themes/shared/in-content/common.inc.css
index a34f36bd6f..191989fc02 100644
--- a/toolkit/themes/shared/in-content/common.inc.css
+++ b/toolkit/themes/shared/in-content/common.inc.css
@@ -44,7 +44,7 @@ html|html,
 xul|page,
 xul|window {
   font: message-box;
-  -moz-appearance: none;
+  appearance: none;
   background-color: var(--in-content-page-background);
   color: var(--in-content-page-color);
 }
@@ -70,7 +70,7 @@ html|hr {
 }
 
 xul|caption {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0;
 }
 
@@ -102,7 +102,7 @@ xul|prefpane > xul|*.content-box {
 /* groupboxes */
 
 xul|groupbox {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   margin: 15px 0 0;
   padding-inline-start: 0;
@@ -120,7 +120,7 @@ xul|groupbox xul|description {
 /* tabpanels and tabs */
 
 xul|tabpanels {
-  -moz-appearance: none;
+  appearance: none;
   font-size: 1.25rem;
   line-height: 22px;
   border: none;
@@ -142,7 +142,7 @@ xul|*.tabs-right {
 }
 
 xul|tab {
-  -moz-appearance: none;
+  appearance: none;
   margin-top: 0;
   padding: 4px 20px;
   min-height: 44px;
@@ -183,7 +183,7 @@ html|button {
 html|select,
 xul|colorpicker[type="button"],
 xul|menulist {
-  -moz-appearance: none;
+  appearance: none;
   min-height: 30px;
   color: var(--in-content-text-color);
   border: 1px solid var(--in-content-box-border-color);
@@ -251,7 +251,7 @@ xul|menulist > xul|*.menulist-label-box > xul|*.menulist-icon[src] {
 }
 
 xul|button[type="menu"] > xul|*.button-box > xul|*.button-menu-dropmarker {
-  -moz-appearance: none;
+  appearance: none;
   margin: 1px 0;
   margin-inline-start: 10px;
   padding: 0;
@@ -359,7 +359,7 @@ xul|*.spinbuttons-down[disabled="true"] > xul|*.button-box > xul|*.button-icon {
 }
 
 xul|menulist:not([editable="true"]) > xul|*.menulist-dropmarker {
-  -moz-appearance: none;
+  appearance: none;
   margin-inline-end: 4px;
   padding: 0;
   border: none;
@@ -378,7 +378,7 @@ xul|menulist[disabled="true"]:not([editable="true"]) > xul|*.menulist-dropmarker
 
 xul|menulist > xul|menupopup,
 xul|button[type="menu"] > xul|menupopup {
-  -moz-appearance: none;
+  appearance: none;
   border: 1px solid var(--in-content-box-border-color);
   border-radius: 2px;
   background-color: var(--in-content-box-background);
@@ -388,7 +388,7 @@ xul|menulist > xul|menupopup xul|menu,
 xul|menulist > xul|menupopup xul|menuitem,
 xul|button[type="menu"] > xul|menupopup xul|menu,
 xul|button[type="menu"] > xul|menupopup xul|menuitem {
-  -moz-appearance: none;
+  appearance: none;
   font-size: 1em;
   color: var(--in-content-text-color);
   padding-top: 0.2em;
@@ -425,7 +425,7 @@ xul|button[type="menu"] > xul|menupopup > xul|menuitem[disabled="true"] {
 
 xul|menulist > xul|menupopup xul|menuseparator,
 xul|button[type="menu"] > xul|menupopup xul|menuseparator {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0;
   padding: 0;
   border-top: 1px solid var(--in-content-box-border-color);
@@ -437,7 +437,7 @@ xul|button[type="menu"] > xul|menupopup xul|menuseparator {
 html|input[type="text"],
 html|textarea,
 xul|textbox {
-  -moz-appearance: none;
+  appearance: none;
   color: var(--in-content-text-color);
   border: 1px solid var(--in-content-box-border-color);
   -moz-border-top-colors: none !important;
@@ -532,7 +532,7 @@ xul|checkbox {
 
 xul|*.checkbox-check,
 html|input[type="checkbox"] + html|label:before {
-  -moz-appearance: none;
+  appearance: none;
   width: 23px;
   height: 23px;
   border-radius: 2px;
@@ -583,7 +583,7 @@ xul|radio {
 }
 
 xul|*.radio-check {
-  -moz-appearance: none;
+  appearance: none;
   width: 23px;
   height: 23px;
   border: 1px solid var(--in-content-box-border-color);
@@ -615,7 +615,7 @@ xul|*.radio-label-box {
 /* Category List */
 
 *|*#categories {
-  -moz-appearance: none;
+  appearance: none;
   background-color: var(--in-content-category-background);
   padding-top: 39px;
   margin: 0;
@@ -623,7 +623,7 @@ xul|*.radio-label-box {
 }
 
 *|*.category {
-  -moz-appearance: none;
+  appearance: none;
   color: var(--in-content-category-text);
   border-inline-end-width: 0;
   padding-inline-start: 15px;
@@ -684,7 +684,7 @@ xul|*.radio-label-box {
 /* File fields */
 
 xul|filefield {
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   border: none;
   padding: 0;
@@ -729,7 +729,7 @@ xul|filefield + xul|button {
 
 xul|richlistbox,
 xul|listbox {
-  -moz-appearance: none;
+  appearance: none;
   margin-inline-start: 0;
   background-color: var(--in-content-box-background);
   border: 1px solid var(--in-content-box-border-color);
@@ -759,7 +759,7 @@ xul|listbox xul|listitem[selected="true"] {
 /* Trees */
 
 xul|tree {
-  -moz-appearance: none;
+  appearance: none;
   font-size: 1em;
   border: 1px solid var(--in-content-box-border-color);
   background-color: var(--in-content-box-background);
@@ -773,7 +773,7 @@ xul|richlistbox:-moz-focusring {
 
 xul|listheader,
 xul|treecols {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   border-bottom: 1px solid var(--in-content-border-color);
   padding: 0;
@@ -785,7 +785,7 @@ xul|treecols {
 
 xul|treecol:not([hideheader="true"]),
 xul|treecolpicker {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background-color: var(--in-content-box-background-hover);
   color: #808080;
diff --git a/toolkit/themes/shared/media/videocontrols.css b/toolkit/themes/shared/media/videocontrols.css
index a40d77fe3a..a42bc1b93b 100644
--- a/toolkit/themes/shared/media/videocontrols.css
+++ b/toolkit/themes/shared/media/videocontrols.css
@@ -17,7 +17,7 @@
   background-color: transparent;
   background-repeat: no-repeat;
   background-position: center;
-  -moz-appearance: none;   /* Remove the native button appearance and styling */
+  appearance: none;   /* Remove the native button appearance and styling */
   margin: 0;
   padding: 0;
   min-height: 28px;
@@ -110,7 +110,7 @@
 
 .textTrackList {
   display: -moz-box;
-  -moz-appearance: none;
+  appearance: none;
   -moz-box-pack: end;
   -moz-box-align: end;
   padding: 0;
@@ -121,7 +121,7 @@
 }
 
 .textTrackList > html|*.textTrackItem {
-  -moz-appearance: none;
+  appearance: none;
   -moz-box-align: start;
   text-align: start;
   overflow: hidden;
@@ -192,7 +192,7 @@
   /* margin top/bottom: make bar 8px tall (control height = 28, minus 2 * 10 margin) */
   /* margin left/right: 1/2 of scrubber thumb width, for overhang. */
   margin: 10px 22px;
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background-color: transparent;
   min-width: 0;
@@ -208,20 +208,20 @@
    */
   background-color: rgba(255,255,255,.5);
   border-radius: 2.5px;
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .progressBar .progress-bar {
   background-color: white;
   border-radius: 2.5px;
-  -moz-appearance: none;
+  appearance: none;
 }
 
 /* .scale-slider is an element inside the <scale> implementation. */
 .scrubber .scale-slider,
 .volumeControl .scale-slider {
   /* Hide the default horizontal bar. */
-  -moz-appearance: none;
+  appearance: none;
   background: none;
   margin: 0;
 }
@@ -235,7 +235,7 @@
 .scrubber .scale-thumb,
 .volumeControl .scale-thumb {
   /* Override the default thumb appearance with a custom image. */
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   border: none;
 }
diff --git a/toolkit/themes/shared/narrate.css b/toolkit/themes/shared/narrate.css
index 836b5d6865..a46199df02 100644
--- a/toolkit/themes/shared/narrate.css
+++ b/toolkit/themes/shared/narrate.css
@@ -177,7 +177,7 @@ body.dark .narrate-word-highlight {
 
 .voiceselect > button.select-toggle,
 .voiceselect > .options > button.option {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   width: 100%;
   min-height: 40px;
diff --git a/toolkit/themes/windows/global/alerts/alert.css b/toolkit/themes/windows/global/alerts/alert.css
index ce7f259126..6d29324617 100644
--- a/toolkit/themes/windows/global/alerts/alert.css
+++ b/toolkit/themes/windows/global/alerts/alert.css
@@ -11,7 +11,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 #alertNotification {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   padding: 10px;
 }
@@ -25,7 +25,7 @@
 }
 
 .alertCloseButton {
-  -moz-appearance: none;
+  appearance: none;
   padding: 4px 2px;
   border: none !important;
 }
diff --git a/toolkit/themes/windows/global/autocomplete.css b/toolkit/themes/windows/global/autocomplete.css
index 79748f2895..094bb3313a 100644
--- a/toolkit/themes/windows/global/autocomplete.css
+++ b/toolkit/themes/windows/global/autocomplete.css
@@ -38,7 +38,7 @@ textbox:not(.padded) .textbox-input-box {
 panel[type="autocomplete"],
 panel[type="autocomplete-richlistbox"],
 .autocomplete-history-popup {
-  -moz-appearance: none;
+  appearance: none;
   border-width: 1px;
   -moz-border-top-colors: ThreeDShadow;
   -moz-border-right-colors: ThreeDShadow;
@@ -56,13 +56,13 @@ panel[type="autocomplete-richlistbox"],
 /* ::::: tree ::::: */
 
 .autocomplete-tree {
-  -moz-appearance: none !important;
+  appearance: none !important;
   border: none !important;
   background-color: transparent !important;
 }
 
 .autocomplete-treecol {
-  -moz-appearance: none !important;
+  appearance: none !important;
   margin: 0 !important;
   border: none !important;
   padding: 0 !important;
@@ -70,7 +70,7 @@ panel[type="autocomplete-richlistbox"],
 
 /* GTK calculates space for a sort arrow */
 .autocomplete-treecol > .treecol-sortdirection {
-  -moz-appearance: none !important;
+  appearance: none !important;
 }
 
 .autocomplete-treebody::-moz-tree-cell-text {
@@ -93,7 +93,7 @@ treechildren.autocomplete-treebody::-moz-tree-cell-text(selected) {
 /* ::::: richlistbox autocomplete ::::: */
 
 .autocomplete-richlistbox {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0;
 }
 
diff --git a/toolkit/themes/windows/global/button.css b/toolkit/themes/windows/global/button.css
index 3aeac85122..b8e3224064 100644
--- a/toolkit/themes/windows/global/button.css
+++ b/toolkit/themes/windows/global/button.css
@@ -11,7 +11,7 @@
 /* :::::::::: button :::::::::: */
 
 button {
-  -moz-appearance: button;
+  appearance: button;
   margin: 1px 5px 2px 5px;
   min-width: 6.3em;
   border: 3px solid;
@@ -120,7 +120,7 @@ button[type="menu-button"] {
 
 .button-menu-dropmarker,
 .button-menubutton-dropmarker {
-  -moz-appearance: none !important;
+  appearance: none !important;
   margin: 1px;
   background-color: transparent;
   border: none;
@@ -147,7 +147,7 @@ button[type="disclosure"] {
   border: 0px !important;
   margin: 0px !important;
   padding: 0px !important;
-  -moz-appearance: none;
+  appearance: none;
   list-style-image: url("chrome://global/skin/tree/twisty.svg#clsd");
   min-width: 0px !important;
   background-color: transparent;
diff --git a/toolkit/themes/windows/global/checkbox.css b/toolkit/themes/windows/global/checkbox.css
index c7719bff2e..00f1f04927 100644
--- a/toolkit/themes/windows/global/checkbox.css
+++ b/toolkit/themes/windows/global/checkbox.css
@@ -11,7 +11,7 @@
 /* ::::: checkbox ::::: */
 
 checkbox {
-  -moz-appearance: checkbox-container;
+  appearance: checkbox-container;
   -moz-box-align: center;
   margin: 2px 4px;
   padding-top: 1px;
@@ -58,7 +58,7 @@ checkbox[disabled="true"]:-moz-system-metric(windows-classic) {
 /* ::::: checkmark image ::::: */
 
 .checkbox-check {
-  -moz-appearance: checkbox;
+  appearance: checkbox;
   -moz-box-align: center;
   border: 2px solid;
   -moz-border-top-colors: ThreeDShadow ThreeDDarkShadow;
diff --git a/toolkit/themes/windows/global/colorpicker.css b/toolkit/themes/windows/global/colorpicker.css
index dfab1e9baa..3ced1bb987 100644
--- a/toolkit/themes/windows/global/colorpicker.css
+++ b/toolkit/themes/windows/global/colorpicker.css
@@ -13,7 +13,7 @@
 /* colorpicker button */
 
 colorpicker[type="button"] {
-  -moz-appearance: button;
+  appearance: button;
   width: 38px;
   height: 24px;
   padding: 3px;
diff --git a/toolkit/themes/windows/global/console/console.css b/toolkit/themes/windows/global/console/console.css
index d646658745..c04f296bd9 100644
--- a/toolkit/themes/windows/global/console/console.css
+++ b/toolkit/themes/windows/global/console/console.css
@@ -211,11 +211,11 @@ toolbar#ToolbarMode .toolbarbutton-text {
 @media not all and (-moz-os-version: windows-win10),
        not all and (-moz-os-version: windows-win11) {
   #ToolbarMode {
-    -moz-appearance: -moz-win-browsertabbar-toolbox;
+    appearance: -moz-win-browsertabbar-toolbox;
   }
 
   #ToolbarEval {
-    -moz-appearance: toolbox;
+    appearance: toolbox;
   }
 }
 %endif
diff --git a/toolkit/themes/windows/global/customizeToolbar.css b/toolkit/themes/windows/global/customizeToolbar.css
index 3c11b9cbe0..5b2c3e2dc0 100644
--- a/toolkit/themes/windows/global/customizeToolbar.css
+++ b/toolkit/themes/windows/global/customizeToolbar.css
@@ -13,7 +13,7 @@ dialog {
 }
 
 #palette-box {
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 0 0 10px;
 }
 
diff --git a/toolkit/themes/windows/global/datetimepicker.css b/toolkit/themes/windows/global/datetimepicker.css
index 255210332d..caf8b4ce1a 100644
--- a/toolkit/themes/windows/global/datetimepicker.css
+++ b/toolkit/themes/windows/global/datetimepicker.css
@@ -18,7 +18,7 @@ datepicker, timepicker {
 }
 
 .datetimepicker-input-box {
-  -moz-appearance: textfield;
+  appearance: textfield;
   cursor: text;
   margin-inline-end: 2px;
   border: 2px solid;
@@ -93,7 +93,7 @@ timepicker[disabled="true"] {
 }
 
 .datepicker-button {
-  -moz-appearance: none;
+  appearance: none;
   min-width: 8px;
   padding: 0px;
 }
diff --git a/toolkit/themes/windows/global/dropmarker.css b/toolkit/themes/windows/global/dropmarker.css
index 34814abd44..c45ac86867 100644
--- a/toolkit/themes/windows/global/dropmarker.css
+++ b/toolkit/themes/windows/global/dropmarker.css
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 dropmarker {
-  -moz-appearance: menulist-button;
+  appearance: menulist-button;
   width: 16px;
   height: 16px;
   -moz-box-align: center;
diff --git a/toolkit/themes/windows/global/filefield.css b/toolkit/themes/windows/global/filefield.css
index e22b64ec6d..e8a97aacc8 100644
--- a/toolkit/themes/windows/global/filefield.css
+++ b/toolkit/themes/windows/global/filefield.css
@@ -8,7 +8,7 @@
 /* File Field Widget */
 filefield {
   margin: 2px 4px;
-  -moz-appearance: textfield;
+  appearance: textfield;
 }
 
 .fileFieldContentBox {
@@ -29,7 +29,7 @@ filefield {
 }
 
 .fileFieldLabel {
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   border: none;
   margin: 0px;
diff --git a/toolkit/themes/windows/global/findBar.css b/toolkit/themes/windows/global/findBar.css
index ecb1b2db13..8afe26888c 100644
--- a/toolkit/themes/windows/global/findBar.css
+++ b/toolkit/themes/windows/global/findBar.css
@@ -7,7 +7,7 @@
 .findbar-closebutton {
   border: none;
   padding: 3px 5px;
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .findbar-closebutton:-moz-lwtheme-brighttext {
@@ -110,7 +110,7 @@ findbar[hidden] {
 }
 
 .findbar-textbox {
-  -moz-appearance: none;
+  appearance: none;
   border: 1px solid ThreeDShadow;
   border-radius: 2px;
   margin: 0;
diff --git a/toolkit/themes/windows/global/global.css b/toolkit/themes/windows/global/global.css
index 0712d19a4f..c032dec5ab 100644
--- a/toolkit/themes/windows/global/global.css
+++ b/toolkit/themes/windows/global/global.css
@@ -36,7 +36,7 @@ page,
 dialog,
 wizard,
 prefwindow {
-  -moz-appearance: window;
+  appearance: window;
   background-color: -moz-Dialog;
   color: -moz-DialogText;
   font: message-box;
@@ -90,7 +90,7 @@ iframe {
 /* ::::: statusbar ::::: */
 
 statusbar {
-  -moz-appearance: statusbar;
+  appearance: statusbar;
   border-top: 1px solid ThreeDLightShadow;
   border-left: 1px solid ThreeDShadow;
   border-right: 1px solid ThreeDHighlight;
@@ -100,7 +100,7 @@ statusbar {
 }
 
 statusbarpanel {
-  -moz-appearance: statusbarpanel;
+  appearance: statusbarpanel;
   -moz-box-align: center;
   -moz-box-pack: center;
   border-left: 1px solid ThreeDHighlight;
@@ -111,7 +111,7 @@ statusbarpanel {
 }
 
 statusbarpanel:not(.statusbar-resizerpanel):-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   border-top-style: none;
   border-bottom-style: none;
   border-inline-start-style: none;
@@ -120,7 +120,7 @@ statusbarpanel:not(.statusbar-resizerpanel):-moz-lwtheme {
 .statusbar-resizerpanel {
   -moz-box-align: end;
   -moz-box-pack: end;
-  -moz-appearance: resizerpanel;
+  appearance: resizerpanel;
   padding: 0;
   border: none;
 }
@@ -136,7 +136,7 @@ statusbarpanel:not(.statusbar-resizerpanel):-moz-lwtheme {
 sidebarheader {
   height: 25px;
   background-color: -moz-Dialog;
-  -moz-appearance: toolbox;
+  appearance: toolbox;
   border-bottom: 1px solid ThreeDShadow;
   border-top: 1px solid ThreeDHighlight;
 }
@@ -158,7 +158,7 @@ toolbar[mode="text"] .toolbarbutton-text {
 
 :root:-moz-lwtheme,
 [lwthemefooter="true"] {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 :root:-moz-lwtheme-darktext {
@@ -171,7 +171,7 @@ toolbar[mode="text"] .toolbarbutton-text {
 
 statusbar:-moz-lwtheme,
 sidebarheader:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   background: none;
   border-style: none;
 }
@@ -224,7 +224,7 @@ separator.groove[orient="vertical"] {
 }
 
 .plain {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0 !important;
   border: none;
   padding: 0;
@@ -313,7 +313,7 @@ popupnotificationcontent {
 %ifdef XP_WIN
   background-position: right top;
 %endif
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .autoscroller[scrolldir="NS"] {
diff --git a/toolkit/themes/windows/global/groupbox.css b/toolkit/themes/windows/global/groupbox.css
index f07c6a5427..b85aff347f 100644
--- a/toolkit/themes/windows/global/groupbox.css
+++ b/toolkit/themes/windows/global/groupbox.css
@@ -11,7 +11,7 @@
 /* ::::: groupbox ::::: */
 
 groupbox {
-  -moz-appearance: groupbox;
+  appearance: groupbox;
   border: 2px groove ThreeDFace;
   border-radius: 3px;
   margin: 3px;
@@ -28,7 +28,7 @@ caption {
 }
 
 tabpanels caption {
-  -moz-appearance: tabpanel;
+  appearance: tabpanel;
 }
 
 /* !important is needed to override label in global.css */
diff --git a/toolkit/themes/windows/global/inContentUI.css b/toolkit/themes/windows/global/inContentUI.css
index a3bca7b06b..4e7deecd66 100644
--- a/toolkit/themes/windows/global/inContentUI.css
+++ b/toolkit/themes/windows/global/inContentUI.css
@@ -11,7 +11,7 @@
 
 /* Page background */
 *|*:root {
-  -moz-appearance: none;
+  appearance: none;
   padding: 18px;
   background-repeat: repeat;
   color: -moz-dialogText;
@@ -91,7 +91,7 @@ html|html {
   *|button,
   menulist,
   colorpicker[type="button"] {
-    -moz-appearance: none;
+    appearance: none;
     color: black;
     padding: 0 5px;
     background: linear-gradient(rgba(251, 252, 253, 0.95), transparent 49%, 
diff --git a/toolkit/themes/windows/global/listbox.css b/toolkit/themes/windows/global/listbox.css
index fd60b16934..01090c4c3b 100644
--- a/toolkit/themes/windows/global/listbox.css
+++ b/toolkit/themes/windows/global/listbox.css
@@ -12,7 +12,7 @@
 /* ::::: listbox ::::: */
 
 listbox {
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 2px 4px;
   border: 2px solid;
   -moz-border-top-colors: ThreeDShadow ThreeDDarkShadow;
@@ -55,7 +55,7 @@ listbox:focus > listitem[selected="true"] {
 /* ::::: listheader ::::: */
 
 listheader {
-  -moz-appearance: treeheadercell;
+  appearance: treeheadercell;
   -moz-box-align: center;
   border: 2px solid;
   -moz-border-top-colors: ThreeDHighlight ThreeDLightShadow;
@@ -134,7 +134,7 @@ listheader[sortable="true"]:hover:active {
 /* ::::: listcell checkbox ::::: */
 
 .listcell-check {
-  -moz-appearance: checkbox;
+  appearance: checkbox;
   -moz-box-align: center;
   margin: 0px 2px;
   border: 1px solid -moz-DialogText;
diff --git a/toolkit/themes/windows/global/menu.css b/toolkit/themes/windows/global/menu.css
index 2a228251d4..c2aab6b8d3 100644
--- a/toolkit/themes/windows/global/menu.css
+++ b/toolkit/themes/windows/global/menu.css
@@ -14,7 +14,7 @@ menu,
 menuitem,
 menucaption,
 .splitmenu-menuitem {
-  -moz-appearance: menuitem;
+  appearance: menuitem;
   -moz-box-align: center;
   color: MenuText;
   font: menu;
@@ -63,7 +63,7 @@ menuitem.spell-suggestion {
 
 .menu-text {
   padding-inline-start: 1.45em !important;
-  -moz-appearance: menuitemtext;
+  appearance: menuitemtext;
 }
 
 .menu-text,
@@ -104,14 +104,14 @@ menucaption > .menu-iconic-text {
 menu.menu-iconic > .menu-iconic-left,
 menuitem.menuitem-iconic > .menu-iconic-left,
 .splitmenu-menuitem[iconic="true"] > .menu-iconic-left {
-  -moz-appearance: menuimage;
+  appearance: menuimage;
   padding-top: 2px;
 }
 
 /* ..... menu arrow box ..... */
 
 .menu-right {
-  -moz-appearance: menuarrow;
+  appearance: menuarrow;
   margin-inline-end: -2px;
   list-style-image: none;
   min-width: 1.28em;
@@ -133,7 +133,7 @@ menubar > menu[_moz-menuactive="true"][open="true"] {
 }
 
 menubar > menu:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   border-color: transparent;
 }
 
@@ -150,7 +150,7 @@ menubar > menu:-moz-lwtheme[_moz-menuactive="true"]:not([disabled="true"]) {
 @media (-moz-windows-default-theme) {
   @media not all and (-moz-os-version: windows-xp) {
     menubar > menu:-moz-lwtheme {
-      -moz-appearance: menuitem;
+      appearance: menuitem;
     }
 
     menubar > menu:-moz-lwtheme[_moz-menuactive="true"]:not([disabled="true"]) {
@@ -197,7 +197,7 @@ menuitem[_moz-menuactive="true"],
 menulist > menupopup > menuitem,
 menulist > menupopup > menucaption,
 menulist > menupopup > menu {
-  -moz-appearance: none !important;
+  appearance: none !important;
   border: 1px solid transparent;
   padding-inline-start: 5px;
   padding-inline-end: 5px;
@@ -246,19 +246,19 @@ menulist > menupopup > :-moz-any(menuitem, menucaption):not(.menuitem-iconic) >
 
 menuitem[type="checkbox"],
 menuitem[checked="true"] {
-  -moz-appearance: checkmenuitem;
+  appearance: checkmenuitem;
 }
 menuitem[type="checkbox"] > .menu-iconic-left,
 menuitem[checked="true"] > .menu-iconic-left {
-  -moz-appearance: menucheckbox;
+  appearance: menucheckbox;
   padding-top: 0px;
 }
 
 menuitem[type="radio"] {
-  -moz-appearance: radiomenuitem;
+  appearance: radiomenuitem;
 }
 menuitem[type="radio"] > .menu-iconic-left {
-  -moz-appearance: menuradio;
+  appearance: menuradio;
   padding-top: 0px;
 }
 
@@ -273,7 +273,7 @@ menuitem[type="radio"] > .menu-iconic-left > .menu-iconic-icon {
 /* ::::: menuseparator ::::: */
 
 menuseparator {
-  -moz-appearance: menuseparator;
+  appearance: menuseparator;
   padding: 3px 1px 4px 1px;
   border-top: 1px solid ThreeDShadow;
   border-bottom: 1px solid ThreeDHighlight;
diff --git a/toolkit/themes/windows/global/menulist.css b/toolkit/themes/windows/global/menulist.css
index 9480bffdaf..b311f1a702 100644
--- a/toolkit/themes/windows/global/menulist.css
+++ b/toolkit/themes/windows/global/menulist.css
@@ -12,7 +12,7 @@
 /* :::::::::: menulist :::::::::: */
 
 menulist {
-  -moz-appearance: menulist;
+  appearance: menulist;
   margin: 2px 4px;
   border: 2px solid;
   -moz-border-top-colors: ThreeDShadow ThreeDDarkShadow;
diff --git a/toolkit/themes/windows/global/notification.css b/toolkit/themes/windows/global/notification.css
index 433a8a006f..e7b2d94024 100644
--- a/toolkit/themes/windows/global/notification.css
+++ b/toolkit/themes/windows/global/notification.css
@@ -57,7 +57,7 @@ notification[type="critical"] {
 }
 
 .messageCloseButton {
-  -moz-appearance: none;
+  appearance: none;
   padding: 4px 2px;
   border: none !important;
 }
@@ -95,7 +95,7 @@ XXX: apply styles to all themes until bug 509642 is fixed
 @media (-moz-windows-default-theme) {
 */
   .popup-notification-menubutton {
-    -moz-appearance: none;
+    appearance: none;
     border-radius: 3px;
     padding: 0;
     background-color: rgba(250,250,250,.3)
@@ -108,7 +108,7 @@ XXX: apply styles to all themes until bug 509642 is fixed
   .popup-notification-menubutton:not([type="menu-button"]),
   .popup-notification-menubutton > .button-menubutton-button,
   .popup-notification-menubutton > .button-menubutton-dropmarker {
-    -moz-appearance: none;
+    appearance: none;
     margin: 0;
     border: 1px solid rgba(0,0,0,.35);
 
diff --git a/toolkit/themes/windows/global/popup.css b/toolkit/themes/windows/global/popup.css
index 010e85a932..e1a81d05c6 100644
--- a/toolkit/themes/windows/global/popup.css
+++ b/toolkit/themes/windows/global/popup.css
@@ -20,7 +20,7 @@ panel {
 }
 
 menupopup {
-  -moz-appearance: menupopup;
+  appearance: menupopup;
 }
 
 menupopup > menu > menupopup {
@@ -30,7 +30,7 @@ menupopup > menu > menupopup {
 }
 
 panel[type="arrow"] {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   border: none;
 }
@@ -127,7 +127,7 @@ panel[type="arrow"][side="right"] {
 /* ::::: tooltip ::::: */
 
 tooltip {
-  -moz-appearance: tooltip;
+  appearance: tooltip;
   margin-top: 21px;
   border: 1px solid InfoText;
   padding: 2px 3px;
@@ -147,7 +147,7 @@ tooltip[titletip="true"] {
 /* rules for popups associated with menulists */
 
 menulist > menupopup {
-  -moz-appearance: none;
+  appearance: none;
   border-width: 1px;
   -moz-border-top-colors: -moz-FieldText;
   -moz-border-right-colors: -moz-FieldText;
diff --git a/toolkit/themes/windows/global/preferences.css b/toolkit/themes/windows/global/preferences.css
index b096358dd4..663e15dc93 100644
--- a/toolkit/themes/windows/global/preferences.css
+++ b/toolkit/themes/windows/global/preferences.css
@@ -43,7 +43,7 @@ prefwindow[type="child"] .prefWindow-dlgbuttons {
 }
 
 radio[pane] {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0px 1px 0px 1px;
   padding: 1px 3px 1px 3px;
   min-width: 4.5em;
@@ -65,12 +65,12 @@ radio[pane] {
 radio[pane]:hover {
   background-color: #E0E8F6;
   color: black;
-  -moz-appearance: none;
+  appearance: none;
 }
 
 radio[pane][selected="true"] {
   background-color: #C1D2EE;
   color: black; 
-  -moz-appearance: none;
+  appearance: none;
 }
 
diff --git a/toolkit/themes/windows/global/progressmeter.css b/toolkit/themes/windows/global/progressmeter.css
index 623fa7ac88..1180a6769f 100644
--- a/toolkit/themes/windows/global/progressmeter.css
+++ b/toolkit/themes/windows/global/progressmeter.css
@@ -11,7 +11,7 @@
 /* ::::: progressmeter ::::: */
 
 progressmeter {
-  -moz-appearance: progressbar;
+  appearance: progressbar;
   margin: 2px 4px;
   border: 2px solid;
   -moz-border-top-colors: ThreeDShadow -moz-Dialog;
@@ -25,7 +25,7 @@ progressmeter {
 
 .progress-bar 
 {
-  -moz-appearance: progresschunk;
+  appearance: progresschunk;
   min-width: 0px;
   background-color: ThreeDShadow;
 }
diff --git a/toolkit/themes/windows/global/radio.css b/toolkit/themes/windows/global/radio.css
index c4a009d057..d13bafa970 100644
--- a/toolkit/themes/windows/global/radio.css
+++ b/toolkit/themes/windows/global/radio.css
@@ -11,7 +11,7 @@
 /* ::::: radio ::::: */
 
 radio {
-  -moz-appearance: radio-container;
+  appearance: radio-container;
   -moz-box-align: center;
   margin: 2px 4px;
   padding-top: 1px;
@@ -61,7 +61,7 @@ radio[disabled="true"]:-moz-system-metric(windows-classic) {
 /* ::::: checkmark image ::::: */
 
 .radio-check-box1 {
-  -moz-appearance: radio;
+  appearance: radio;
   margin: 1px 0px;
   border-top: 1px solid ThreeDShadow;
   border-right: 1px solid ThreeDHighlight;
diff --git a/toolkit/themes/windows/global/resizer.css b/toolkit/themes/windows/global/resizer.css
index 8108d7e85a..2eb1b94c5f 100644
--- a/toolkit/themes/windows/global/resizer.css
+++ b/toolkit/themes/windows/global/resizer.css
@@ -5,7 +5,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 resizer {
-  -moz-appearance: resizer;
+  appearance: resizer;
   background: url("chrome://global/skin/icons/resizer.png") no-repeat;
   background-size: 100% 100%;
   cursor: se-resize;
diff --git a/toolkit/themes/windows/global/richlistbox.css b/toolkit/themes/windows/global/richlistbox.css
index 90c6e672a6..38f847cd38 100644
--- a/toolkit/themes/windows/global/richlistbox.css
+++ b/toolkit/themes/windows/global/richlistbox.css
@@ -5,7 +5,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 richlistbox {
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 2px 4px;
   background-color: -moz-Field;
   color: -moz-FieldText;
diff --git a/toolkit/themes/windows/global/scale.css b/toolkit/themes/windows/global/scale.css
index 4812546164..2c945dc1f8 100644
--- a/toolkit/themes/windows/global/scale.css
+++ b/toolkit/themes/windows/global/scale.css
@@ -7,7 +7,7 @@
 /* ::::: scale ::::: */
 
 .scale-slider {
-  -moz-appearance: scale-horizontal;
+  appearance: scale-horizontal;
   background: url("chrome://global/skin/scale/scale-tray-horiz.gif") 0% 50% repeat-x;
   margin: 2px 4px;
   width: 100px;
@@ -15,7 +15,7 @@
 
 .scale-slider[orient="vertical"]
 {
-  -moz-appearance: scale-vertical;
+  appearance: scale-vertical;
   background: url("chrome://global/skin/scale/scale-tray-vert.gif") 50% 0% repeat-y;
   margin: 4px 2px;
   width: auto;
@@ -25,7 +25,7 @@
 /* ::::: scale thumb ::::: */
 
 .scale-thumb {
-  -moz-appearance: scalethumb-horizontal;
+  appearance: scalethumb-horizontal;
   border: 2px solid;
   -moz-border-top-colors: ThreeDLightShadow ThreeDHighlight;
   -moz-border-right-colors: ThreeDDarkShadow ThreeDShadow;
@@ -37,7 +37,7 @@
 }
 
 .scale-thumb[orient="vertical"] {
-  -moz-appearance: scalethumb-vertical;
+  appearance: scalethumb-vertical;
   min-width: 15px;
   min-height: 30px;
 }
diff --git a/toolkit/themes/windows/global/spinbuttons.css b/toolkit/themes/windows/global/spinbuttons.css
index a2f2ebf49a..8a48394ec9 100644
--- a/toolkit/themes/windows/global/spinbuttons.css
+++ b/toolkit/themes/windows/global/spinbuttons.css
@@ -5,7 +5,7 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 spinbuttons {
-  -moz-appearance: spinner;
+  appearance: spinner;
   cursor: default;
 }
 
@@ -43,7 +43,7 @@ spinbuttons {
 }
 
 .spinbuttons-up {
-  -moz-appearance: spinner-upbutton;
+  appearance: spinner-upbutton;
   background-image: url("chrome://global/skin/arrow/arrow-up.gif");
   background-position: center center;
   background-repeat: no-repeat;
@@ -54,7 +54,7 @@ spinbuttons {
 }
 
 .spinbuttons-down {
-  -moz-appearance: spinner-downbutton;
+  appearance: spinner-downbutton;
   background-image: url("chrome://global/skin/arrow/arrow-dn.gif");
   background-position: center center;
   background-repeat: no-repeat;
diff --git a/toolkit/themes/windows/global/tabbox.css b/toolkit/themes/windows/global/tabbox.css
index 6a414cc4e3..277001529c 100644
--- a/toolkit/themes/windows/global/tabbox.css
+++ b/toolkit/themes/windows/global/tabbox.css
@@ -19,7 +19,7 @@
 /* ::::: tabpanels ::::: */
 
 tabpanels {
-  -moz-appearance: tabpanels; 
+  appearance: tabpanels; 
   border-right: 2px solid;
   border-bottom: 2px solid;
   border-left: 2px solid;
@@ -35,7 +35,7 @@ tabpanels {
 
 tab 
 {
-  -moz-appearance: tab;
+  appearance: tab;
   margin-top: 2px;
   border-top: 2px solid;
   border-right: 2px solid;
diff --git a/toolkit/themes/windows/global/textbox.css b/toolkit/themes/windows/global/textbox.css
index 78ca7f3205..0c26423722 100644
--- a/toolkit/themes/windows/global/textbox.css
+++ b/toolkit/themes/windows/global/textbox.css
@@ -12,7 +12,7 @@
 /* ::::: textbox ::::: */
 
 textbox {
-  -moz-appearance: textfield;
+  appearance: textfield;
   cursor: text;
   margin: 2px 4px;
   border: 2px solid;
@@ -66,7 +66,7 @@ textbox[disabled="true"] {
 /* ::::: plain textbox ::::: */
 
 textbox.plain {
-  -moz-appearance: none !important;
+  appearance: none !important;
   background-color: transparent;
   padding: 0px !important;
   margin: 0px !important;
diff --git a/toolkit/themes/windows/global/toolbar.css b/toolkit/themes/windows/global/toolbar.css
index 486cdf0be5..fbc4de8d48 100644
--- a/toolkit/themes/windows/global/toolbar.css
+++ b/toolkit/themes/windows/global/toolbar.css
@@ -11,7 +11,7 @@
 /* ::::: toolbox ::::: */
 
 toolbox {
-  -moz-appearance: toolbox;
+  appearance: toolbox;
   background-color: -moz-Dialog;
   border-top: 2px solid;
   -moz-border-top-colors: ThreeDShadow ThreeDHighlight;
@@ -23,7 +23,7 @@ toolbox {
     /* Windows 10/11's "aero" msstyle sourced toolbox background is pure white
        so don't use the widget toolbox styling and fallback to -moz-Dialog's
        color which by default should be a non-blinding rgb(240, 240, 240) */
-    -moz-appearance: none;
+    appearance: none;
 
     /* Since we are overriding the style we want to provide the bottom border
        that is normally drawn by look&feel.
@@ -36,7 +36,7 @@ toolbox {
 /* ::::: toolbar & menubar ::::: */
 
 toolbar, menubar {
-  -moz-appearance: toolbar;
+  appearance: toolbar;
 }
 
 toolbar {
@@ -58,7 +58,7 @@ toolbar:first-child, menubar {
 menubar:-moz-lwtheme,
 toolbox:-moz-lwtheme,
 toolbar:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   background: none;
   border-color: transparent;
 }
@@ -66,7 +66,7 @@ toolbar:-moz-lwtheme {
 menubar:-moz-lwtheme,
 toolbox:-moz-lwtheme,
 toolbar:-moz-lwtheme {
-  -moz-appearance: none;
+  appearance: none;
   background: none;
   border-style: none;
 }
@@ -75,7 +75,7 @@ toolbar:-moz-lwtheme {
 /* ::::: toolbar decorations ::::: */
 
 toolbarseparator {
-  -moz-appearance: separator;
+  appearance: separator;
   border-top: 2px solid transparent;
   border-bottom: 2px solid transparent;
   border-left: 3px solid transparent;
diff --git a/toolkit/themes/windows/global/toolbarbutton.css b/toolkit/themes/windows/global/toolbarbutton.css
index e96e529cf3..7afe6a8b0e 100644
--- a/toolkit/themes/windows/global/toolbarbutton.css
+++ b/toolkit/themes/windows/global/toolbarbutton.css
@@ -11,7 +11,7 @@
 /* ::::: toolbarbutton ::::: */
 
 toolbarbutton {
-  -moz-appearance: toolbarbutton;
+  appearance: toolbarbutton;
   -moz-box-align: center;
   -moz-box-pack: center;
   margin: 0;
@@ -36,9 +36,9 @@ toolbarbutton.tabbable {
 }
 
 toolbarbutton:-moz-focusring {
-  /* -moz-appearance looks redundant here but is necessary.
+  /* appearance looks redundant here but is necessary.
       Without it, the outline won't appear. */
-  -moz-appearance: toolbarbutton;
+  appearance: toolbarbutton;
   outline: 1px dotted -moz-DialogText;
   outline-offset: -2px;
 }
@@ -99,7 +99,7 @@ toolbarbutton[checked="true"]:not([disabled="true"]) {
 
 @media not all and (-moz-windows-default-theme) {
   toolbarbutton:-moz-lwtheme {
-    -moz-appearance: none;
+    appearance: none;
   }
 
   toolbarbutton:-moz-lwtheme:not([disabled="true"]) {
@@ -111,7 +111,7 @@ toolbarbutton[checked="true"]:not([disabled="true"]) {
 /* ::::: toolbarbutton menu ::::: */
 
 .toolbarbutton-menu-dropmarker {
-  -moz-appearance: none !important;
+  appearance: none !important;
   border: none !important;
   background-color: transparent !important;
   padding: 0;
@@ -172,7 +172,7 @@ toolbarbutton[type="menu-button"][disabled="true"]:hover:active {
 /* .......... dropmarker .......... */
 
 .toolbarbutton-menubutton-dropmarker {
-  -moz-appearance: none;
+  appearance: none;
   padding: 3px 7px;
   border: none;
   background-color: transparent;
diff --git a/toolkit/themes/windows/global/tree.css b/toolkit/themes/windows/global/tree.css
index e2e0f8c40a..1c8b2d908b 100644
--- a/toolkit/themes/windows/global/tree.css
+++ b/toolkit/themes/windows/global/tree.css
@@ -19,7 +19,7 @@ tree {
   -moz-border-left-colors: ThreeDShadow ThreeDDarkShadow;
   background-color: -moz-Field;
   color: -moz-FieldText;
-  -moz-appearance: listbox;
+  appearance: listbox;
 }
 
 /* ::::: tree focusring ::::: */
@@ -209,7 +209,7 @@ treechildren::-moz-tree-cell-text(progressmeter) {
 
 treecol,
 treecolpicker {
-  -moz-appearance: treeheadercell;
+  appearance: treeheadercell;
   -moz-box-align: center;
   -moz-box-pack: center;
   border: 2px solid;
@@ -231,7 +231,7 @@ treecolpicker {
 }
 
 treecol[hideheader="true"] {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   padding: 0;
 }
@@ -367,7 +367,7 @@ treechildren::-moz-tree-cell-text(active, selected, editing) {
 }
 
 .tree-input {
-  -moz-appearance: none;
+  appearance: none;
   border: 1px solid Highlight;
   -moz-border-top-colors: Highlight;
   -moz-border-bottom-colors: Highlight;
diff --git a/toolkit/themes/windows/global/xulscrollbars.css b/toolkit/themes/windows/global/xulscrollbars.css
index 53f2376059..3a8fa716fe 100644
--- a/toolkit/themes/windows/global/xulscrollbars.css
+++ b/toolkit/themes/windows/global/xulscrollbars.css
@@ -12,7 +12,7 @@
 /* ::::: scrollbar ::::: */
 
 scrollbar {
-  -moz-appearance: scrollbar-horizontal;
+  appearance: scrollbar-horizontal;
   -moz-binding: url("chrome://global/content/bindings/scrollbar.xml#scrollbar");
   cursor: default;
   background: url("chrome://global/skin/scrollbar/slider.gif") scrollbar;
@@ -32,7 +32,7 @@ scrollbar {
 
 scrollbar[orient="vertical"] 
 {
-   -moz-appearance: scrollbar-vertical;
+   appearance: scrollbar-vertical;
 }
 
 /* ::::: borders for thumb and buttons ::::: */
@@ -49,22 +49,22 @@ scrollbarbutton {
 
 /* ::::: slider - a thumb is inside  ::::: */
 slider {
-  -moz-appearance: scrollbartrack-horizontal;
+  appearance: scrollbartrack-horizontal;
 }
 
 slider[orient="vertical"] {
-  -moz-appearance: scrollbartrack-vertical;
+  appearance: scrollbartrack-vertical;
 }
 
 /* ::::: thumb (horizontal) ::::: */
 
 thumb {
-  -moz-appearance: scrollbarthumb-vertical;
+  appearance: scrollbarthumb-vertical;
   min-height: 8px;
 }
 
 thumb[orient="horizontal"] {
-  -moz-appearance: scrollbarthumb-horizontal;
+  appearance: scrollbarthumb-horizontal;
   min-width: 8px;
 }
 
@@ -85,7 +85,7 @@ scrollbarbutton:hover:active, scrollbarbutton[active="true"] {
 /* ::::: square at the corner of two scrollbars ::::: */
 
 scrollcorner { 
-  /* XXX -moz-appearance: scrollcorner; */
+  /* XXX appearance: scrollcorner; */
   -moz-binding: url(chrome://global/content/bindings/scrollbar.xml#scrollbar-base);
   width: 16px;
   cursor: default;
@@ -95,7 +95,7 @@ scrollcorner {
 /* ..... increment .... */
 
 scrollbarbutton[type="increment"] {
-  -moz-appearance: scrollbarbutton-right;
+  appearance: scrollbarbutton-right;
   background-image: url("chrome://global/skin/arrow/arrow-rit.gif")
 }
 
@@ -104,7 +104,7 @@ scrollbarbutton[type="increment"][disabled="true"] {
 }
 
 scrollbar[orient="vertical"] > scrollbarbutton[type="increment"] {
-  -moz-appearance: scrollbarbutton-down;
+  appearance: scrollbarbutton-down;
   background-image: url("chrome://global/skin/arrow/arrow-dn.gif")
 }
 
@@ -115,7 +115,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="increment"][disabled="true"
 /* ..... decrement .... */
 
 scrollbarbutton[type="decrement"] {
-  -moz-appearance: scrollbarbutton-left;
+  appearance: scrollbarbutton-left;
    background-image: url("chrome://global/skin/arrow/arrow-lft.gif")
 }
 
@@ -124,7 +124,7 @@ scrollbarbutton[type="decrement"][disabled="true"] {
 }
 
 scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"] {
-  -moz-appearance: scrollbarbutton-up;
+  appearance: scrollbarbutton-up;
    background-image: url("chrome://global/skin/arrow/arrow-up.gif")
 }
 
@@ -139,7 +139,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   /* ::::: scrollbar ::::: */
 
   html|div scrollbar {
-    -moz-appearance: scrollbar-horizontal;
+    appearance: scrollbar-horizontal;
     -moz-binding: url("chrome://global/content/bindings/scrollbar.xml#scrollbar");
     cursor: default;
     background: url("chrome://global/skin/scrollbar/slider.gif") scrollbar;
@@ -147,7 +147,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
 
   html|div scrollbar[orient="vertical"] 
   {
-     -moz-appearance: scrollbar-vertical;
+     appearance: scrollbar-vertical;
   }
 
   /* ::::: borders for thumb and buttons ::::: */
@@ -165,12 +165,12 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   /* ::::: thumb (horizontal) ::::: */
 
   html|div thumb {
-    -moz-appearance: scrollbarthumb-vertical;
+    appearance: scrollbarthumb-vertical;
     min-height: 8px;
   }
 
   html|div thumb[orient="horizontal"] {
-    -moz-appearance: scrollbarthumb-horizontal;
+    appearance: scrollbarthumb-horizontal;
     min-width: 8px;
   }
 
@@ -193,7 +193,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   /* ..... increment .... */
 
   html|div scrollbarbutton[type="increment"] {
-    -moz-appearance: scrollbarbutton-right;
+    appearance: scrollbarbutton-right;
     background-image: url("chrome://global/skin/arrow/arrow-rit.gif")
   }
 
@@ -202,7 +202,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   }
 
   html|div scrollbar[orient="vertical"] > scrollbarbutton[type="increment"] {
-    -moz-appearance: scrollbarbutton-down;
+    appearance: scrollbarbutton-down;
     background-image: url("chrome://global/skin/arrow/arrow-dn.gif")
   }
 
@@ -213,7 +213,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   /* ..... decrement .... */
 
   html|div scrollbarbutton[type="decrement"] {
-    -moz-appearance: scrollbarbutton-left;
+    appearance: scrollbarbutton-left;
      background-image: url("chrome://global/skin/arrow/arrow-lft.gif")
   }
 
@@ -222,7 +222,7 @@ scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"][disabled="true"
   }
 
   html|div scrollbar[orient="vertical"] > scrollbarbutton[type="decrement"] {
-    -moz-appearance: scrollbarbutton-up;
+    appearance: scrollbarbutton-up;
      background-image: url("chrome://global/skin/arrow/arrow-up.gif")
   }
 
diff --git a/toolkit/themes/windows/mozapps/downloads/downloads.css b/toolkit/themes/windows/mozapps/downloads/downloads.css
index 3f1bcbec31..6c2cf73a2c 100644
--- a/toolkit/themes/windows/mozapps/downloads/downloads.css
+++ b/toolkit/themes/windows/mozapps/downloads/downloads.css
@@ -9,7 +9,7 @@
 /* Download View */
 @media not all and (-moz-windows-classic) {
   #downloadView {
-    -moz-appearance: none;
+    appearance: none;
     margin: 0;
     border-bottom: 2px solid;
     -moz-border-bottom-colors: ThreeDHighlight ThreeDLightShadow;
@@ -32,7 +32,7 @@ richlistitem[type="download"] .dateTime {
 }
 
 .mini-button {
-  -moz-appearance: none;
+  appearance: none;
   list-style-image: url(chrome://mozapps/skin/downloads/downloadButtons.png);
   background-color: transparent;
   border: none;
@@ -113,13 +113,13 @@ richlistitem[type="download"] .dateTime {
 
 @media (-moz-windows-compositor) and (-moz-os-version: windows-win7) {
   #downloadManager {
-    -moz-appearance: -moz-win-glass;
+    appearance: -moz-win-glass;
     background: transparent;
   }
 
   #downloadView {
     /* Clamp glass bounds to the rich list so our glass haze stays constant. */
-    -moz-appearance: -moz-win-exclude-glass;
+    appearance: -moz-win-exclude-glass;
     border: none;
   }
 
diff --git a/toolkit/themes/windows/mozapps/extensions/about.css b/toolkit/themes/windows/mozapps/extensions/about.css
index 7188c11bf9..97e3aae780 100644
--- a/toolkit/themes/windows/mozapps/extensions/about.css
+++ b/toolkit/themes/windows/mozapps/extensions/about.css
@@ -16,12 +16,12 @@
 
 @media (-moz-windows-compositor) {
   #genericAbout {
-    -moz-appearance: -moz-win-glass;
+    appearance: -moz-win-glass;
     background: transparent;
   }
 
   #clientBox {
-    -moz-appearance: -moz-win-exclude-glass;
+    appearance: -moz-win-exclude-glass;
   }
 }
 
diff --git a/toolkit/themes/windows/mozapps/extensions/eula.css b/toolkit/themes/windows/mozapps/extensions/eula.css
index 5fb2c52df2..a8754994c2 100644
--- a/toolkit/themes/windows/mozapps/extensions/eula.css
+++ b/toolkit/themes/windows/mozapps/extensions/eula.css
@@ -34,7 +34,7 @@
 }
 
 #eula {
-  -moz-appearance: none;
+  appearance: none;
   color: -moz-FieldText;
   background-color: -moz-Field;
   margin: 1em;
diff --git a/toolkit/themes/windows/mozapps/extensions/extensions.css b/toolkit/themes/windows/mozapps/extensions/extensions.css
index 51d95af86b..4cc39eb8ab 100644
--- a/toolkit/themes/windows/mozapps/extensions/extensions.css
+++ b/toolkit/themes/windows/mozapps/extensions/extensions.css
@@ -158,7 +158,7 @@
 /*** category selector ***/
 
 #categories {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   -moz-margin-end: -1px;
   background-color: transparent;
@@ -167,7 +167,7 @@
 }
 
 .category {
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   color: #252F3B;
   min-height: 0;
@@ -302,7 +302,7 @@
 
 @media (-moz-windows-default-theme) {
   #header-search {
-    -moz-appearance: none;
+    appearance: none;
     border: 1px solid rgba(0, 0, 0, 0.32);
     padding-bottom: 2px;
     background-color: rgba(255, 255, 255, 0.4);
@@ -351,11 +351,11 @@
 /*** sorters ***/
 
 .sort-controls {
-  -moz-appearance: none;
+  appearance: none;
 }
 
 .sorter {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background-color: transparent;
   color: #536680;
@@ -427,7 +427,7 @@
 /*** list ***/
 
 .list {
-  -moz-appearance: none;
+  appearance: none;
   margin: 0;
   border: none;
   background-color: transparent;
@@ -606,7 +606,7 @@
 }
 
 .addon .relnotes-toggle {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   background: transparent;
   font-weight: bold;
@@ -710,7 +710,7 @@
 }
 
 .search-filter-radio {
-  -moz-appearance: none;
+  appearance: none;
   padding: 0 6px;
   margin: 0 3px;
   border-radius: 10000px;
@@ -837,7 +837,7 @@
 }
 
 #detail-contrib-btn {
-  -moz-appearance: none;
+  appearance: none;
   color: #FFF;
   border: 1px solid #3A4EEE;
   border-radius: 3px;
@@ -998,7 +998,7 @@ menulist { /* Fixes some styling inconsistencies */
 .download-progress[complete] .end-cap,
 .download-progress[mode="undetermined"] .end-cap,
 .download-progress .progress .progress-bar {
-  -moz-appearance: none;
+  appearance: none;
   background-image: linear-gradient(#92DDA0, #6FC483 49%, #5EB272 51%, #80CE91);
   margin-top: -1px;
   margin-bottom: -1px;
@@ -1023,7 +1023,7 @@ menulist { /* Fixes some styling inconsistencies */
 }
 
 .download-progress .progress {
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   padding: 0;
   margin: 0;
@@ -1046,7 +1046,7 @@ menulist { /* Fixes some styling inconsistencies */
 }
 
 .download-progress .cancel {
-  -moz-appearance: none;
+  appearance: none;
   background-color: rgba(255, 255, 255, 0.4);
   border: 1px solid rgba(0, 0, 0, 0.4);
   padding: 3px;
@@ -1128,7 +1128,7 @@ menulist { /* Fixes some styling inconsistencies */
 }
 
 button.button-link {
-  -moz-appearance: none;
+  appearance: none;
   background: transparent;
   border: none;
   box-shadow: none;
@@ -1156,7 +1156,7 @@ button.button-link:not([disabled="true"]):active:hover {
 }
 
 .header-button {
-  -moz-appearance: none;
+  appearance: none;
   padding: 1px 3px;
   color: #444;
   text-shadow: 0 0 3px white;
diff --git a/toolkit/themes/windows/mozapps/extensions/xpinstallConfirm.css b/toolkit/themes/windows/mozapps/extensions/xpinstallConfirm.css
index d038e1abf3..4f081ad4e8 100644
--- a/toolkit/themes/windows/mozapps/extensions/xpinstallConfirm.css
+++ b/toolkit/themes/windows/mozapps/extensions/xpinstallConfirm.css
@@ -7,7 +7,7 @@
 }
 
 #itemList {
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 3px 4px 10px 4px;
   height: 14em;
   border: 2px solid;
@@ -67,7 +67,7 @@ installitem {
 }
 
 .xpinstallItemURL {
-  -moz-appearance: none;
+  appearance: none;
   border: none;
   padding: 0;
   background-color: -moz-Field;
diff --git a/toolkit/themes/windows/mozapps/plugins/pluginInstallerWizard.css b/toolkit/themes/windows/mozapps/plugins/pluginInstallerWizard.css
index 2337ca1997..c6a9322aa9 100644
--- a/toolkit/themes/windows/mozapps/plugins/pluginInstallerWizard.css
+++ b/toolkit/themes/windows/mozapps/plugins/pluginInstallerWizard.css
@@ -1,5 +1,5 @@
 #licenseContainer, #pluginList {
-  -moz-appearance: listbox;
+  appearance: listbox;
   margin: 2px 4px;
   border: 2px solid;
   -moz-border-top-colors: ThreeDShadow ThreeDDarkShadow;
diff --git a/toolkit/themes/windows/mozapps/update/updates.css b/toolkit/themes/windows/mozapps/update/updates.css
index daf5222309..d4e5778d10 100644
--- a/toolkit/themes/windows/mozapps/update/updates.css
+++ b/toolkit/themes/windows/mozapps/update/updates.css
@@ -62,7 +62,7 @@ wizardpage {
 #pauseButton {
   list-style-image: url(chrome://mozapps/skin/update/downloadButtons.png);
   -moz-image-region: rect(0px, 48px, 16px, 32px);
-  -moz-appearance: none;
+  appearance: none;
   background-color: transparent;
   border: none;
   min-width: 0;
@@ -137,7 +137,7 @@ update {
 }
 
 #historyItems {
-  -moz-appearance: listbox;
+  appearance: listbox;
   height: 200px;
   margin: 1px 5px 4px 5px;
 }
diff --git a/widget/cocoa/nsCocoaWindow.mm b/widget/cocoa/nsCocoaWindow.mm
index 40b357a056..d168ed6f55 100644
--- a/widget/cocoa/nsCocoaWindow.mm
+++ b/widget/cocoa/nsCocoaWindow.mm
@@ -3316,7 +3316,7 @@ static const NSString* kStateCollectionBehavior = @"collectionBehavior";
 // This class also provides us with a pill button to show/hide the toolbar up to 10.6.
 //
 // Drawing the unified gradient in the titlebar and the toolbar works like this:
-// 1) In the style sheet we set the toolbar's -moz-appearance to toolbar.
+// 1) In the style sheet we set the toolbar's appearance to "toolbar".
 // 2) When the toolbar is visible and we paint the application chrome
 //    window, the array that Gecko passes nsChildView::UpdateThemeGeometries
 //    will contain an entry for the widget type NS_THEME_TOOLBAR.
diff --git a/widget/windows/nsNativeThemeWin.cpp b/widget/windows/nsNativeThemeWin.cpp
index cb14f74f69..3f548e67ba 100644
--- a/widget/windows/nsNativeThemeWin.cpp
+++ b/widget/windows/nsNativeThemeWin.cpp
@@ -1021,7 +1021,7 @@ nsNativeThemeWin::GetThemePartAndState(nsIFrame* aFrame, uint8_t aWidgetType,
     case NS_THEME_PROGRESSBAR:
     case NS_THEME_PROGRESSBAR_VERTICAL: {
       // Note IsVerticalProgress only tests for orient css attrribute,
-      // NS_THEME_PROGRESSBAR_VERTICAL is dedicated to -moz-appearance:
+      // NS_THEME_PROGRESSBAR_VERTICAL is dedicated to appearance:
       // progressbar-vertical.
       bool vertical = IsVerticalProgress(aFrame) ||
                       aWidgetType == NS_THEME_PROGRESSBAR_VERTICAL;