remove --proton-tab-block-margin dummy variables

chrome/autohide_tabstoolbar.css

@@ -3,9 +3,6 @@ See the above repository for updates as well as full license text. */
 
 /* Hide tabs unless cursor is on top of toolbar */
 
-/* Dummy variable to support both versions 89-90 */
-:root{ --tab-block-margin: var(--proton-tab-block-margin) }
-
 :root:not([customizing]) #navigator-toolbox{
   position: relative;
   z-index: 1;

chrome/click_selected_tab_to_focus_urlbar.css

@@ -10,8 +10,6 @@ See the above repository for updates as well as full license text. */
 /* Make selected tab unclickable so click goes to the capture box, obviously it can't be clicked at all anymore */
 /* remove the :not([pinned]) bit to make clicking pinned tab AROUND the tab-icon focus urlbar*/
 
-:root{ --tab-block-margin: var(--proton-tab-block-margin) }
-
 .tabbrowser-tab:not([pinned])[selected]{ pointer-events: none }
 
 /* Add back pointer-events to several elements so UI remains usable */

chrome/curved_tabs.css

@@ -6,7 +6,6 @@ See the above repository for updates as well as full license text. */
 #tabbrowser-tabs{
   --uc-tab-curve-size:17px; /* 10px looks about like chromium - 17px looks close to Australis tabs */
   --uc-tabs-scrollbutton-border: 0px;
-  --proton-tab-block-margin:0px;
   --tab-block-margin:0px;
   --tab-min-height: 34px;
   --uc-tab-line-color: rgb(10, 132, 255);

chrome/hide_tabs_with_one_tab.css

@@ -4,9 +4,6 @@ See the above repository for updates as well as full license text. */
 /* Makes tabs toolbar items zero-height initially and sets enlarge them to fill up space equal to tab-min-height set on tabs. Optionally use privatemode_indicator_as_menu_button.css to replace main menu icon with private browsing indicator while tabs are hidden. */
 /* Firefox 65+ only */
 
-/* Dummy variable to support both versions 89-90 */
-:root{ --tab-block-margin: var(--proton-tab-block-margin) }
-
 :root[sizemode="normal"] #nav-bar{ --uc-window-drag-space-width: 20px }
 
 #titlebar{ -moz-appearance: none !important; }

chrome/hide_tabs_with_one_tab_w_window_controls.css

@@ -11,9 +11,6 @@ Get window_control_placeholder_support.css
 Window controls will be all wrong without it
 */
 
-/* Dummy variable to support both versions 89-90 */
-:root{ --tab-block-margin: var(--proton-tab-block-margin,0px) }
-
 #titlebar{ -moz-appearance: none !important; }
 /* We'll use window controls from menubar instead */
 #TabsToolbar > .titlebar-buttonbox-container { display: none }

chrome/multi-row_tabs.css

@@ -29,9 +29,6 @@ See the above repository for updates as well as full license text. */
 
 @-moz-document url(chrome://browser/content/browser.xhtml){
   
-  /* Dummy variable to support both versions 89-90 */
-  :root{ --tab-block-margin: var(--proton-tab-block-margin) }
-  
   #scrollbutton-up~spacer,
   #scrollbutton-up,
   #scrollbutton-down{ display: var(--scrollbutton-display-model,initial) }

chrome/navbar_tabs_oneliner.css

@@ -8,10 +8,9 @@ See the above repository for updates as well as full license text. */
 /*
 urlbar_popup_full_width.css is VERY MUCH recommended for Firefox 71+ because of new urlbar popup
 */
-:root{ --tab-block-margin: var(--proton-tab-block-margin) }
+
 :root[uidensity="compact"]{
   --tab-block-margin: 2px !important;
-  --proton-tab-block-margin: 2px !important;
 }
 
 /* Modify these to change relative widths or default height */

chrome/navbar_tabs_oneliner_tabs_on_left.css

@@ -8,10 +8,9 @@ See the above repository for updates as well as full license text. */
 Get window_control_placeholder_support.css
 Window controls will be all wrong without it
 */
-:root{ --tab-block-margin: var(--proton-tab-block-margin) }
+
 :root[uidensity="compact"]{
   --tab-block-margin: 2px !important;
-  --proton-tab-block-margin: 2px !important;
   }
 
 /* Modify these to change relative widths or default height */

chrome/navbar_tabs_responsive_oneliner.css

@@ -11,10 +11,9 @@ See the above repository for updates as well as full license text. */
 
 /* Modify it to suit your needs */
 @media screen and (min-width: 1100px){
-  :root{ --tab-block-margin: var(--proton-tab-block-margin) }
+
   :root[uidensity="compact"]{
     --tab-block-margin: 2px !important;
-    --proton-tab-block-margin: 2px !important;
     }
   
   /* Modify these to change relative widths or default height */

chrome/non_floating_sharp_tabs.css

@@ -6,7 +6,6 @@ See the above repository for updates as well as full license text. */
  * It's not strictly a requirement, but this style expects compact_proton.css to be loaded before it. */
 
 :root[id]{
-  --proton-tab-block-margin: 0px !important;
   --tab-block-margin: 0px !important;
   --tabs-shadow-size: 1px !important;
   

chrome/overlay_menubar.css

@@ -3,9 +3,6 @@ See the above repository for updates as well as full license text. */
 
 /* Makes menubar appear as overlay in the top left corner */
 
-/* Dummy variable to support both versions 89-90 */
-:root{ --tab-block-margin: var(--proton-tab-block-margin) }
-
 #toolbar-menubar{
   position: fixed;
   display: flex;