make autohide_menubar and toolbars_below_content work together

This change adds a few variables to both styles that "communicate" with
each other. This autohide_menubar is pretty useful if toolbars are
below content so while this does introduce complexity, it's probably worth it.

chrome/autohide_menubar.css

@@ -1,10 +1,13 @@
 /* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/autohide_menubar.css made available under Mozilla Public License v. 2.0
 See the above repository for updates as well as full license text. */
 
-/* Makes menubar behave like on mac */
+/* Makes menubar slide over tabs toolbar when hovered */
 /* Menubar will be shown when cursor touches top of the spacers on both side of tabs. Window controls will be in menubar, so they are automatically hidden */
 /* Make sure you have menubar enabled */
 
+:root{ --uc-menubar-spacer: 6px }
+:root[sizemode="maximized"]{ --uc-menubar-spacer: 1px }
+
 #nav-bar-customization-target,
 #PanelUI-button,
 #nav-bar-overflow-button,
@@ -22,7 +25,8 @@ See the above repository for updates as well as full license text. */
   display: flex;
   width: 100vw; 
   height: var(--uc-menubar-height);
-  margin-top: calc(8px - var(--uc-menubar-height));
+  /* --uc-menubar-extra-margin is defined in toolbars_below_content.css */
+  margin-top: calc(var(--uc-menubar-spacer) - var(--uc-menubar-height) + var(--uc-menubar-extra-margin,0px));
   transition: margin-top 150ms linear !important;
   -moz-window-dragging: no-drag;
   z-index:4;
@@ -30,7 +34,7 @@ See the above repository for updates as well as full license text. */
 
 #toolbar-menubar:hover{
   background-color: var(--toolbar-bgcolor) !important;
-  margin-top: 0px;
+  margin-top: var(--uc-menubar-extra-margin,0px) !important;
   z-index: 6
 }