Bug 1862237 - Reset macOS menuitem spacing in toolbar menus. r=desktop-theme-reviewers,dao

Differential Revision: https://phabricator.services.mozilla.com/D192347

browser/themes/shared/customizableui/panelUI-shared.css

@@ -249,6 +249,11 @@ toolbarseparator + .panel-subview-body {
     margin-top: calc(-1 * (var(--panel-subview-body-padding-block) + var(--panel-shadow-margin) + 1px));
   }
 
+  menuitem::before,
+  menuitem::after {
+    content: none; /* Reset's macOS' checkmark spacing */
+  }
+
   :is(menu, menuitem)[disabled] {
     color: var(--panel-disabled-color);
   }

toolkit/themes/osx/global/in-content/common.css

@@ -12,9 +12,9 @@ xul|tabs {
   position: static;
 }
 
-xul|menulist > xul|menupopup > xul|menuitem::after,
-xul|menulist > xul|menupopup > xul|menuitem::before {
-  display: none;
+xul|menupopup > xul|menuitem::after,
+xul|menupopup > xul|menuitem::before {
+  content: none;
 }
 
 xul|menulist > xul|menupopup xul|menu,

toolkit/themes/osx/global/menu.css

@@ -94,13 +94,12 @@ menulist > menupopup > menu {
 
 menupopup > menuitem {
   padding-inline: 0;
-}
 
   /* We only show the ::before pseudo-element, but we'd like the spacing to be
    * symmetric, so we render an invisible checkmark on both sides in order to
    * reserve the right amount of space. */
-menupopup > menuitem::after,
-menupopup > menuitem::before {
+  &::before,
+  &::after {
     content: '\2713'; /* a checkmark */
     display: inline-block;
     vertical-align: middle;
@@ -108,6 +107,7 @@ menupopup > menuitem::before {
     visibility: hidden;
     padding-inline: 4px;
   }
+}
 
 menupopup > menuitem:is([checked="true"], [selected="true"])::before {
   visibility: inherit;