feat: Always use the system theme when using custom colors, b=no-bug, c=workspaces

src/toolkit/mozapps/extensions/content/aboutaddons-css.patch

@@ -0,0 +1,18 @@
+diff --git a/toolkit/mozapps/extensions/content/aboutaddons.css b/toolkit/mozapps/extensions/content/aboutaddons.css
+index d8f84dcbf83d4768b9b8174ccf07706702d690a5..afce2630bf64a262b0f6a9e752db5c745167bf6a 100644
+--- a/toolkit/mozapps/extensions/content/aboutaddons.css
++++ b/toolkit/mozapps/extensions/content/aboutaddons.css
+@@ -105,6 +105,13 @@ h2 {
+ .category[name="theme"] {
+   background-image: url("chrome://mozapps/skin/extensions/category-themes.svg");
+ }
++
++@media -moz-pref('zen.theme.disable-lightweight') {
++  .category[name="theme"] {
++    display: none;
++  }
++}
++
+ .category[name="plugin"] {
+   background-image: url("chrome://mozapps/skin/extensions/category-plugins.svg");
+ }

src/zen/workspaces/ZenGradientGenerator.mjs

@@ -1110,7 +1110,7 @@
         return forToolbar
           ? this.getToolbarModifiedBase()
           : this.isDarkMode
-            ? 'rgba(0, 0, 0, 0.6)'
+            ? 'rgba(0, 0, 0, 0.45)'
             : 'transparent';
       } else if (themedColors.length === 1) {
         return this.getSingleRGBColor(themedColors[0], forToolbar);
@@ -1501,14 +1501,15 @@
           );
           browser.gZenThemePicker.isLegacyVersion = this.isLegacyVersion;
           let isDarkMode = isDarkModeWindow;
-          if (!isDefaultTheme && !this.isLegacyVersion) {
+          const isUsingCustomColors = workspaceTheme.gradientColors.some((color) => color.isCustom);
+          if (!isDefaultTheme && !this.isLegacyVersion && !isUsingCustomColors) {
             // Check for the primary color
             isDarkMode = browser.gZenThemePicker.shouldBeDarkMode(dominantColor);
             browser.document.documentElement.setAttribute('zen-should-be-dark-mode', isDarkMode);
             browser.gZenThemePicker.panel.removeAttribute('invalidate-controls');
           } else {
             browser.document.documentElement.removeAttribute('zen-should-be-dark-mode');
-            if (!this.isLegacyVersion) {
+            if (!this.isLegacyVersion && !isUsingCustomColors) {
               browser.gZenThemePicker.panel.setAttribute('invalidate-controls', 'true');
             }
           }

src/zen/workspaces/zen-workspaces.css

@@ -22,7 +22,6 @@
     display: none !important;
   }
 
-  --toolbarbutton-hover-background: transparent !important;
   border-radius: var(--zen-button-border-radius) !important;
   background: transparent;
   appearance: unset !important;