diff --git a/FireFox/theme/built_in.css b/FireFox/theme/built_in.css
index 3c4dc185..47e421bc 100644
--- a/FireFox/theme/built_in.css
+++ b/FireFox/theme/built_in.css
@@ -12,7 +12,7 @@
     background-color: var(--lwt-accent-color) !important;
   }
 }
-@supports -moz-bool-pref("layout.css.osx-font-smoothing.enabled") {
+@media (-moz-bool-pref: "layout.css.osx-font-smoothing.enabled") {
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"]) #navigator-toolbox,
   :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"] #navigator-toolbox,
   :root[style*="--lwt-accent-color: rgb(237, 237, 241); --lwt-text-color: rgba(21, 20, 26);"] #navigator-toolbox {
diff --git a/FireFox/theme/fully_color.css b/FireFox/theme/fully_color.css
index 0272ff8f..a65062b6 100644
--- a/FireFox/theme/fully_color.css
+++ b/FireFox/theme/fully_color.css
@@ -65,7 +65,7 @@
     --toolbarbutton-hover-background: rgba(232, 224, 255, 0.11999999731779099) !important;
   }
 }
-@supports -moz-bool-pref("userChrome+Content.theme.non_native_menu") {
+@media (-moz-bool-pref: "userChrome+Content.theme.non_native_menu") {
   @media (-moz-gtk-csd-available) {
     :is(html#main-window, window:is(#places, #bookmarksPanel, #history-panel))
       menupopup:not(.in-menulist) {
diff --git a/FireFox/theme/non_native_menu.css b/FireFox/theme/non_native_menu.css
index 30f689ec..daee113b 100644
--- a/FireFox/theme/non_native_menu.css
+++ b/FireFox/theme/non_native_menu.css
@@ -1,5 +1,5 @@
 /** Non Native Menu ******************************************************************/
-@supports -moz-bool-pref("userChrome+Content.theme.non_native_menu") {
+@media (-moz-bool-pref: "userChrome+Content.theme.non_native_menu") {
   @media (-moz-gtk-csd-available) {
     :root {
       /* Override some menu color variables for light browser themes. */
diff --git a/FireFox/theme/proton_color.css b/FireFox/theme/proton_color.css
index cbccc453..f50021d1 100644
--- a/FireFox/theme/proton_color.css
+++ b/FireFox/theme/proton_color.css
@@ -238,7 +238,7 @@
     --menu-icon-opacity: var(--dark-menu-icon-opacity);
   }
 }
-@supports -moz-bool-pref("userChrome+Content.theme.non_native_menu") {
+@media (-moz-bool-pref: "userChrome+Content.theme.non_native_menu") {
   @media (-moz-gtk-csd-available) {
     :root {
       /* Override some menu color variables for light browser themes. */
diff --git a/FireFox/theme/system_default_theme/cool_breeze.css b/FireFox/theme/system_default_theme/cool_breeze.css
index fbc9dc86..712f66a2 100644
--- a/FireFox/theme/system_default_theme/cool_breeze.css
+++ b/FireFox/theme/system_default_theme/cool_breeze.css
@@ -1,4 +1,4 @@
-@supports -moz-bool-pref("userChrome+Content.theme.cool_breeze") {
+@media (-moz-bool-pref: "userChrome+Content.theme.cool_breeze") {
   :root:is(#main-window):not(:-moz-lwtheme, [privatebrowsingmode=temporary]) {
     --win-component-bgcolor: rgb(163, 198, 218) !important;
   }
diff --git a/FireFox/theme/system_default_theme/private_mode.css b/FireFox/theme/system_default_theme/private_mode.css
index d2fe6f2e..3634acfc 100644
--- a/FireFox/theme/system_default_theme/private_mode.css
+++ b/FireFox/theme/system_default_theme/private_mode.css
@@ -1,6 +1,6 @@
 /*= Private Theme Mode ==============================================================*/
-@supports -moz-bool-pref("userChrome+Content.theme.private_mode") {
-  @supports not -moz-bool-pref("browser.theme.dark-private-windows") {
+@media (-moz-bool-pref: "userChrome+Content.theme.private_mode") {
+  @media (not (-moz-bool-pref: "browser.theme.dark-private-windows")) {
     :root[privatebrowsingmode=temporary]:not(:-moz-lwtheme) {
       --win-text-color: rgb(255, 255, 255);
       --win-bgcolor: #2b2b2b;
@@ -42,7 +42,7 @@
       --win-urlbar-popup-accent-color: rgb(143, 196, 236);
       --win-urlbar-popup-hover-active-bgcolor: rgb(69, 69, 69);
     }
-    @supports -moz-bool-pref("userChrome+Content.compatibility.os.win11") {
+    @media (-moz-bool-pref: "userChrome+Content.compatibility.os.win11") {
       :root[privatebrowsingmode=temporary]:not(:-moz-lwtheme) {
         --win-bgcolor: #202020;
         --win-hover-bgcolor: #383838; /* also button-bgcolor */
@@ -175,7 +175,7 @@
   }
 }
 /*= Private Theme Mode =======================================================*/
-@supports -moz-bool-pref("userChrome+Content.theme.private") {
+@media (-moz-bool-pref: "userChrome+Content.theme.private") {
   :root[privatebrowsingmode="temporary"],
   :root[lwtheme-mozlightdark]:not([lwthemetextcolor="bright"])[privatebrowsingmode="temporary"],
   :root[style*="--lwt-accent-color: rgb(240, 240, 244); --lwt-text-color: rgba(21, 20, 26);"][privatebrowsingmode="temporary"],
diff --git a/FireFox/theme/system_default_theme/win10.css b/FireFox/theme/system_default_theme/win10.css
index 17560517..fac2d5f1 100644
--- a/FireFox/theme/system_default_theme/win10.css
+++ b/FireFox/theme/system_default_theme/win10.css
@@ -43,7 +43,7 @@
     --win-urlbar-popup-hover-active-bgcolor: rgb(193, 193, 193);
 
   }
-  @supports -moz-bool-pref("userChrome+Content.compatibility.os.win11") {
+  @media (-moz-bool-pref: "userChrome+Content.compatibility.os.win11") {
     :root:not(:-moz-lwtheme) {
       --win-text-color: #1a1a1a;
       --win-bgcolor: #e8e8e8;
@@ -112,7 +112,7 @@
     --win-urlbar-popup-accent-color: rgb(143, 196, 236);
     --win-urlbar-popup-hover-active-bgcolor: rgb(69, 69, 69);
   }
-  @supports -moz-bool-pref("userChrome+Content.compatibility.os.win11") {
+  @media (-moz-bool-pref: "userChrome+Content.compatibility.os.win11") {
     :root:not(:-moz-lwtheme) {
       --win-bgcolor: #202020;
       --win-hover-bgcolor: #383838; /* also button-bgcolor */
@@ -153,7 +153,7 @@
     --tab-selected-bgcolor: unset !important;
     --tab-icon-overlay-fill: var(--win-text-color) !important;
     --tab-icon-overlay-stroke: var(--win-field-bgcolor) !important;
-    --tab-line-color: Highlight !important;
+    --tab-line-color: AccentColor !important;
     --tabs-border-color: transparent !important;
     /* Toolbar */
     --toolbar-color: var(--win-text-color) !important;
@@ -237,7 +237,7 @@
     --arrowpanel-border-color: var(--win-bgcolor) !important;
     --panel-separator-color: var(--win-bgcolor) !important;
   }
-  @supports -moz-bool-pref("userChrome+Content.compatibility.os.win11") {
+  @media (-moz-bool-pref: "userChrome+Content.compatibility.os.win11") {
     :root:not(:-moz-lwtheme) {
       --chrome-content-separator-color: var(--win11-chrome-separator-color) !important;
     }