Various improvements to multi-row_tabs_below_content.css

This patch makes the style behave better on linux as well as make
fullscreen mode work better. It also fixes an issue where invisible
menubar would prevent window from being draggable from flexible-space
placed to the left of urlbar.

chrome/multi-row_tabs_below_content.css

@@ -27,7 +27,17 @@ See the above repository for updates as well as full license text. */
     --uc-window-drag-space-width: 30px;
     --uc-window-control-width: 138px;
   }
-
+  :root[inFullscreen]{
+    --uc-window-drag-space-width: 0px;
+  }
+  @media (-moz-gtk-csd-available){
+    :root{
+      --uc-window-control-width:  94px;
+    }
+  }
+  #main-window[tabsintitlebar]{
+    background-color: var(--toolbar-bgcolor,accentcolor) !important;;
+  }
   :root[uidensity="compact"]{ --multirow-toolbar-height: 34px }
   :root{ border-top-width: 0px !important }
 
@@ -35,7 +45,9 @@ See the above repository for updates as well as full license text. */
     -moz-box-ordinal-group: 2;
     border-bottom: 0px !important;
   }
-  
+  #navigator-toolbox{
+    border-bottom: none !important;
+  }
   /* Re-order window and tab notification boxes */
   #navigator-toolbox > div{ display: contents }
   .global-notificationbox,
@@ -59,35 +71,39 @@ See the above repository for updates as well as full license text. */
     width: calc(100vw - var(--uc-window-control-width) - var(--uc-window-drag-space-width));
   }
 
-  :root[inFullscreen] #TabsToolbar > #window-controls{
-    display: flex !important;
-    justify-content: flex-end;
-    position: fixed;
-    right: 0;
-    width: 138px;
-    height: var(--multirow-toolbar-height);
-    background:var(--toolbar-bgcolor);
+  #TabsToolbar > .titlebar-buttonbox-container{
+    display: none !important;
   }  
-
   /* Fix incorrect vertical alignment with megabar */
   #urlbar[breakout]{ --urlbar-toolbar-height: var(--multirow-toolbar-height) !important; }
 
   /* Fix customization view */
   #customization-panelWrapper > .panel-arrowbox > .panel-arrow{ margin-inline-end: initial !important; }
   
+  /* Fullscreen mode support */
   #customization-container,
   :root:not([inFullscreen]) #content-deck,
   :root:not([inFullscreen]) #browser{
-    margin-top: calc(var(--multirow-toolbar-height) + var(--multirow-top-padding) + var(--multirow-menubar-height,0px))
+    margin-top: calc(var(--multirow-toolbar-height) + var(--multirow-top-padding) + var(--multirow-menubar-height,0px));
   }
-
-  :root[inFullscreen] #TabsToolbar > #window-controls,
   :root[inFullscreen] #toolbar-menubar,
-  :root[inFullscreen] #nav-bar{ top: calc(1px - (var(--multirow-toolbar-height) + var(--multirow-top-padding))) }
-
-  :root[inFullscreen] #navigator-toolbox:hover > #titlebar > #TabsToolbar > #window-controls,
+  :root[inFullscreen] #nav-bar{
+    top: calc(1px - (var(--multirow-toolbar-height) + var(--multirow-top-padding)));
+  }
   :root[inFullscreen] #navigator-toolbox:hover > #nav-bar,
-  :root[inFullscreen] #navigator-toolbox:hover > #titlebar > #toolbar-menubar{ top: 0px }
+  :root[inFullscreen] #navigator-toolbox:hover > #titlebar > #toolbar-menubar{
+    top: 0px;
+  }
+  #navigator-toolbox[inFullscreen]{
+    margin-top: 0 !important;
+  }
+  #navigator-toolbox[inFullscreen][style*="margin-top"]:not(:hover){
+    max-height: 0px;
+  }
+  #fullscr-toggler{ bottom: 0; top: unset !important; }
+  :root[inFullscreen] #navigator-toolbox:hover #toolbar-menubar{
+    pointer-events: none !important;
+  }
   
   /* Restyle nav-bar and menubar */
   #nav-bar-customization-target{ flex-grow: 1 }
@@ -101,6 +117,7 @@ See the above repository for updates as well as full license text. */
     display: flex;
     visibility: visible !important;
     top: var(--multirow-top-padding);
+    padding-top: 0 !important;
     width: 100vw;
     color: var(--lwt-text-color);
     background: linear-gradient(to right, var(--toolbar-bgcolor), var(--toolbar-bgcolor) 30px, transparent 30px) no-repeat;
@@ -118,13 +135,16 @@ See the above repository for updates as well as full license text. */
     visibility: visible;
     background-image: linear-gradient( to left,transparent,var(--lwt-accent-color) 35px);
   }
-
+  #toolbar-menubar:not(:hover,[customizing]) *{-moz-window-dragging: drag !important;}
   #toolbar-menubar > .titlebar-buttonbox-container{
     background: var(--toolbar-bgcolor);
     order:1000;
   }
   #menubar-items + spacer{ order: 1000 }
-  #toolbar-menubar > .titlebar-buttonbox-container > .titlebar-buttonbox{ height: 100% ;}
+  #toolbar-menubar > .titlebar-buttonbox-container > .titlebar-buttonbox{
+    height: 100%;
+    pointer-events: auto !important;
+  }
 
   #main-menubar:last-child{ padding-inline-end: 40px }
   #toolbar-menubar > toolbarspring {
@@ -199,7 +219,6 @@ See the above repository for updates as well as full license text. */
   
   /* Hide some things that are unnecessary in multi-row below content mode */
 
-  #TabsToolbar > #window-controls,
   #alltabs-button,
   :root:not([customizing]) #TabsToolbar #new-tab-button,
   #tabbrowser-arrowscrollbox > spacer,