diff --git a/devtools/shared/css/generated/properties-db.js b/devtools/shared/css/generated/properties-db.js
index 8227254aae92..957ef7944b13 100644
--- a/devtools/shared/css/generated/properties-db.js
+++ b/devtools/shared/css/generated/properties-db.js
@@ -6756,15 +6756,9 @@ exports.CSS_PROPERTIES = {
     "supports": [],
     "values": [
       "-moz-button",
-      "-moz-desktop",
-      "-moz-dialog",
-      "-moz-document",
       "-moz-field",
-      "-moz-info",
       "-moz-list",
       "-moz-pull-down-menu",
-      "-moz-window",
-      "-moz-workspace",
       "all-petite-caps",
       "all-small-caps",
       "bold",
diff --git a/gfx/thebes/gfxMacPlatformFontList.mm b/gfx/thebes/gfxMacPlatformFontList.mm
index 9284a96fe603..5fa1b977dcbb 100644
--- a/gfx/thebes/gfxMacPlatformFontList.mm
+++ b/gfx/thebes/gfxMacPlatformFontList.mm
@@ -1866,9 +1866,6 @@ void gfxMacPlatformFontList::LookupSystemFont(LookAndFeel::FontID aSystemFontID,
       break;
 
     case LookAndFeel::FontID::Icon:  // used in urlbar; tried labelFont, but too small
-    case LookAndFeel::FontID::MozWorkspace:
-    case LookAndFeel::FontID::MozDesktop:
-    case LookAndFeel::FontID::MozInfo:
       font = [NSFont controlContentFontOfSize:0.0];
       systemFontName = (char*)kSystemFont_system;
       break;
@@ -1880,7 +1877,6 @@ void gfxMacPlatformFontList::LookupSystemFont(LookAndFeel::FontID aSystemFontID,
 
     case LookAndFeel::FontID::Caption:
     case LookAndFeel::FontID::Menu:
-    case LookAndFeel::FontID::MozDialog:
     default:
       font = [NSFont systemFontOfSize:0.0];
       systemFontName = (char*)kSystemFont_system;
diff --git a/layout/forms/test/test_unstyled_control_height.html b/layout/forms/test/test_unstyled_control_height.html
index 9b0b33763ce6..ad5cd125d25f 100644
--- a/layout/forms/test/test_unstyled_control_height.html
+++ b/layout/forms/test/test_unstyled_control_height.html
@@ -10,9 +10,9 @@
     /* Reduce the width so that container can fit all its children in 600px viewport width. */
     width: 100px;
   }
-  input[type=date] {
-    /* date by default uses a monospace font, which might have different metrics */
-    font: -moz-field;
+  /* date by default uses a monospace font, which might have different metrics */
+  input, button, select {
+    font: Menu;
   }
   .small-font * {
     font-size: 8px !important; /* important to override rule above */
diff --git a/layout/style/crashtests/1382672.html b/layout/style/crashtests/1382672.html
index 9e8eea5baec6..86526e840eb8 100644
--- a/layout/style/crashtests/1382672.html
+++ b/layout/style/crashtests/1382672.html
@@ -4,7 +4,7 @@
 <meta charset="UTF-8">
 <script>
 window.onload = () => {
-  document.documentElement.animate([ { "font": "-moz-desktop" }, { "font": "message-box" } ])
+  document.documentElement.animate([ { "font": "menu" }, { "font": "message-box" } ])
 }
 </script>
 </head>
diff --git a/layout/style/test/property_database.js b/layout/style/test/property_database.js
index e27fc0b9dd88..db30f627cf1e 100644
--- a/layout/style/test/property_database.js
+++ b/layout/style/test/property_database.js
@@ -5544,17 +5544,6 @@ var gCSSProperties = {
       "message-box",
       "small-caption",
       "status-bar",
-      // Gecko-specific system fonts
-      "-moz-window",
-      "-moz-document",
-      "-moz-desktop",
-      "-moz-info",
-      "-moz-dialog",
-      "-moz-button",
-      "-moz-pull-down-menu",
-      "-moz-list",
-      "-moz-field",
-      "-moz-workspace",
       // line-height with calc()
       "condensed bold italic small-caps 24px/calc(2px) Times New Roman, serif",
       "condensed bold italic small-caps 24px/calc(50%) Times New Roman, serif",
diff --git a/layout/style/test/test_non_content_accessible_values.html b/layout/style/test/test_non_content_accessible_values.html
index 2e0786fc3f71..7ba1cf9f05e1 100644
--- a/layout/style/test/test_non_content_accessible_values.html
+++ b/layout/style/test/test_non_content_accessible_values.html
@@ -22,6 +22,12 @@ const NON_CONTENT_ACCESSIBLE_VALUES = {
     "-moz-box",
     "-moz-inline-box",
   ],
+  "font": [
+      "-moz-pull-down-menu",
+      "-moz-button",
+      "-moz-list",
+      "-moz-field",
+  ],
   "-moz-appearance": [
     "button-arrow-down",
     "button-arrow-next",
diff --git a/layout/style/test/test_value_storage.html b/layout/style/test/test_value_storage.html
index b1d483d92b74..542cad91ed42 100644
--- a/layout/style/test/test_value_storage.html
+++ b/layout/style/test/test_value_storage.html
@@ -48,24 +48,18 @@
  * cserialize.
  */
 
-var gSystemFont = {
-  "caption": true,
-  "icon": true,
-  "menu": true,
-  "message-box": true,
-  "small-caption": true,
-  "status-bar": true,
-  "-moz-window": true,
-  "-moz-document": true,
-  "-moz-desktop": true,
-  "-moz-info": true,
-  "-moz-dialog": true,
-  "-moz-button": true,
-  "-moz-pull-down-menu": true,
-  "-moz-list": true,
-  "-moz-field": true,
-  "-moz-workspace": true,
-};
+var gSystemFont = [
+  "caption",
+  "icon",
+  "menu",
+  "message-box",
+  "small-caption",
+  "status-bar",
+  "-moz-button",
+  "-moz-pull-down-menu",
+  "-moz-list",
+  "-moz-field",
+];
 
 var gBadCompute = {
   // output wrapped around to positive, in exponential notation
@@ -154,7 +148,7 @@ function test_property(property)
 
   function test_value(value, resolved_value) {
     var value_has_variable_reference = resolved_value != null;
-    var is_system_font = property == "font" && value in gSystemFont;
+    var is_system_font = property == "font" && gSystemFont.includes(value);
 
     var colon = ": ";
     gDeclaration.setProperty(property, value, "");
diff --git a/servo/components/style/properties/shorthands/font.mako.rs b/servo/components/style/properties/shorthands/font.mako.rs
index 4faa1b98076e..d373204220ed 100644
--- a/servo/components/style/properties/shorthands/font.mako.rs
+++ b/servo/components/style/properties/shorthands/font.mako.rs
@@ -69,7 +69,7 @@
         let mut stretch = None;
         let size;
         % if engine == "gecko":
-            if let Ok(sys) = input.try_parse(SystemFont::parse) {
+            if let Ok(sys) = input.try_parse(|i| SystemFont::parse(context, i)) {
                 return Ok(expanded! {
                      % for name in SYSTEM_FONT_LONGHANDS:
                         ${name}: ${name}::SpecifiedValue::system_font(sys),
diff --git a/servo/components/style/values/specified/font.rs b/servo/components/style/values/specified/font.rs
index 1a37f26c250c..cd61737bf085 100644
--- a/servo/components/style/values/specified/font.rs
+++ b/servo/components/style/values/specified/font.rs
@@ -70,21 +70,29 @@ macro_rules! system_font_methods {
 )]
 #[allow(missing_docs)]
 pub enum SystemFont {
+    /// https://drafts.csswg.org/css-fonts/#valdef-font-caption
     Caption,
+    /// https://drafts.csswg.org/css-fonts/#valdef-font-icon
     Icon,
+    /// https://drafts.csswg.org/css-fonts/#valdef-font-menu
     Menu,
+    /// https://drafts.csswg.org/css-fonts/#valdef-font-message-box
     MessageBox,
+    /// https://drafts.csswg.org/css-fonts/#valdef-font-small-caption
     SmallCaption,
+    /// https://drafts.csswg.org/css-fonts/#valdef-font-status-bar
     StatusBar,
-    MozWindow,
-    MozDocument,
-    MozWorkspace,
-    MozDesktop,
-    MozInfo,
-    MozDialog,
-    MozButton,
+    /// Internal system font, used by the `<menupopup>`s on macOS.
+    #[parse(condition = "ParserContext::in_ua_or_chrome_sheet")]
     MozPullDownMenu,
+    /// Internal system font, used for `<button>` elements.
+    #[parse(condition = "ParserContext::in_ua_or_chrome_sheet")]
+    MozButton,
+    /// Internal font, used by `<select>` elements.
+    #[parse(condition = "ParserContext::in_ua_or_chrome_sheet")]
     MozList,
+    /// Internal font, used by `<input>` elements.
+    #[parse(condition = "ParserContext::in_ua_or_chrome_sheet")]
     MozField,
     #[css(skip)]
     End, // Just for indexing purposes.
diff --git a/toolkit/themes/osx/reftests/checkboxsize.xhtml b/toolkit/themes/osx/reftests/checkboxsize.xhtml
index f0bfb3912e22..1e5c62535e37 100644
--- a/toolkit/themes/osx/reftests/checkboxsize.xhtml
+++ b/toolkit/themes/osx/reftests/checkboxsize.xhtml
@@ -16,7 +16,7 @@ checkbox {
   <vbox style="font: message-box">
     <hbox><checkbox native="true" label="Small"/></hbox>
   </vbox>
-  <vbox style="font: -moz-dialog">
+  <vbox style="font: menu">
     <hbox><checkbox native="true" label="Regular"/></hbox>
   </vbox>
   <vbox style="font-size: 9px">
@@ -25,7 +25,7 @@ checkbox {
   <vbox style="font: message-box">
     <hbox><checkbox native="true" label="Small" checked="true"/></hbox>
   </vbox>
-  <vbox style="font: -moz-dialog">
+  <vbox style="font: menu">
     <hbox><checkbox native="true" label="Regular" checked="true"/></hbox>
   </vbox>
 </window>
diff --git a/toolkit/themes/osx/reftests/radiosize.xhtml b/toolkit/themes/osx/reftests/radiosize.xhtml
index 44f735db07fc..15b4d5dd9287 100644
--- a/toolkit/themes/osx/reftests/radiosize.xhtml
+++ b/toolkit/themes/osx/reftests/radiosize.xhtml
@@ -16,7 +16,7 @@ radio {
   <vbox style="font: message-box">
     <hbox><radio label="Small"/></hbox>
   </vbox>
-  <vbox style="font: -moz-dialog">
+  <vbox style="font: menu">
     <hbox><radio label="Regular"/></hbox>
   </vbox>
   <vbox style="font-size: 9px">
@@ -25,7 +25,7 @@ radio {
   <vbox style="font: message-box">
     <hbox><radio label="Small" selected="true"/></hbox>
   </vbox>
-  <vbox style="font: -moz-dialog">
+  <vbox style="font: menu">
     <hbox><radio label="Regular" selected="true"/></hbox>
   </vbox>
 </window>
diff --git a/widget/cocoa/nsLookAndFeel.mm b/widget/cocoa/nsLookAndFeel.mm
index 7d9222566d66..ddbabf09b64e 100644
--- a/widget/cocoa/nsLookAndFeel.mm
+++ b/widget/cocoa/nsLookAndFeel.mm
@@ -557,20 +557,6 @@ bool nsLookAndFeel::IsSystemOrientationRTL() {
 bool nsLookAndFeel::NativeGetFont(FontID aID, nsString& aFontName, gfxFontStyle& aFontStyle) {
   NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
 
-  // hack for now
-  if (aID == FontID::MozWindow || aID == FontID::MozDocument) {
-    aFontStyle.style = mozilla::FontSlantStyle::NORMAL;
-    aFontStyle.weight = mozilla::FontWeight::NORMAL;
-    aFontStyle.stretch = mozilla::FontStretch::NORMAL;
-    aFontStyle.size = 14;
-    aFontStyle.systemFont = true;
-
-    aFontName.AssignLiteral("sans-serif");
-    return true;
-  }
-
-  // TODO: Add caching? Note that it needs to be thread-safe for stylo use.
-
   nsAutoCString name;
   gfxPlatformMac::LookupSystemFont(aID, name, aFontStyle);
   aFontName.Append(NS_ConvertUTF8toUTF16(name));
diff --git a/widget/gtk/nsLookAndFeel.cpp b/widget/gtk/nsLookAndFeel.cpp
index f8c680c3ac0a..a2fb76f3ee49 100644
--- a/widget/gtk/nsLookAndFeel.cpp
+++ b/widget/gtk/nsLookAndFeel.cpp
@@ -1090,12 +1090,6 @@ bool nsLookAndFeel::PerThemeData::GetFont(FontID aID, nsString& aFontName,
     case FontID::MessageBox:    // css2
     case FontID::SmallCaption:  // css2
     case FontID::StatusBar:     // css2
-    case FontID::MozWindow:     // css3
-    case FontID::MozDocument:   // css3
-    case FontID::MozWorkspace:  // css3
-    case FontID::MozDesktop:    // css3
-    case FontID::MozInfo:       // css3
-    case FontID::MozDialog:     // css3
     default:
       aFontName = mDefaultFontName;
       aFontStyle = mDefaultFontStyle;
diff --git a/widget/windows/nsLookAndFeel.cpp b/widget/windows/nsLookAndFeel.cpp
index 96ac8822d157..13d3a540a633 100644
--- a/widget/windows/nsLookAndFeel.cpp
+++ b/widget/windows/nsLookAndFeel.cpp
@@ -744,7 +744,6 @@ LookAndFeelFont nsLookAndFeel::GetLookAndFeelFont(LookAndFeel::FontID anID) {
     case LookAndFeel::FontID::StatusBar:
       result = GetLookAndFeelFontInternal(ncm.lfStatusFont, false);
       break;
-    case LookAndFeel::FontID::MozDialog:
     case LookAndFeel::FontID::MozButton:
     case LookAndFeel::FontID::MozField:
     case LookAndFeel::FontID::MozList: