ShadowFox/userChrome-files/windows_fixes/context_menus.css

 /* Remove white separators between menu items */
 menupopup menuseparator {
   -moz-appearance:none !important;
   background: rgba(0, 0, 0, 0) !important;
   border: 0px !important;
 }

 /* Removes white bar between icons and menu items */
 #context-navigation, #context-sep-navigation {
   padding: 0px !important;
 }

 /* Bookmark Toolbar, fix border */
 #BMB_bookmarksPopup menupopup {
   padding: 4px 0px 0px 0px  !important;
 }

 /* Context menus, border added because Windows has a different drop shadow effect than macOS */
 #personal-bookmarks menupopup,
 .panel-arrowcontent,
 .box-inherit scrollbox-innerbox,
 #BMB_bookmarksPopup menupopup[placespopup="true"] > hbox,
 menupopup#BMB_bookmarksPopup > menu > menupopup > hbox,
 menupopup#bookmarksMenuPopup > menu > menupopup,
 menupopup#bookmarksMenuPopup menupopup[placespopup="true"],
 menupopup#contentAreaContextMenu,
 menupopup#contentAreaContextMenu menupopup,
 menupopup#placesContext,
 menupopup#bookmarksMenuPopup,
 menupopup#PlacesChevronPopup,
 menupopup#toolbar-context-menu,
 menupopup#downloadsContextMenu,
 menupopup#tabContextMenu,
 menupopup#tabContextMenu menupopup,
 toolbaritem#menubar-items menupopup {
   border-color: var(--primary-dark-color) !important;
   border-width: 1px !important;
   border-style: solid !important;
 }

 /* Bookmarks Toolbar, Toolbar Context menu, LEFT/RIGHT padding fixes */
 #personal-bookmarks menupopup .bookmark-item,
 #bookmarksMenuPopup,
 menupopup#goPopup {
   padding-left: 4px !important;
   padding-right: 4px !important;
 }

 /* Tab menu, LEFT/RIGHT padding fixes */
 menupopup#tabContextMenu > menu > menupopup > .popup-internal-box,
 menupopup#toolbar-context-menu,
 menupopup#contentAreaContextMenu menupopup {
   padding-left: 2px !important;
   padding-right: 2px !important;
 }

 /* Context menus, TOP/BOTTOM padding fixes */
 menupopup,
 menupopup > menu > menupopup {
   padding: 4px 0px 4px 0px  !important;
 }

 /* Menus, text size to match macOS */
 menupopup#contentAreaContextMenu > menuitem,
 menupopup#contentAreaContextMenu > menu,
 #PlacesToolbar menupopup > menuitem,
 #PlacesToolbar menupopup > menu,
 menupopup#tabContextMenu > menuitem,
 menupopup#tabContextMenu > menu,
 menupopup#tabContextMenu menupopup > menuitem,
 menupopup#tabContextMenu menupopup > menu,
 menupopup#toolbar-context-menu > menuitem ,
 menupopup#placesContext menuitem {
   font-size: 1.167em !important;
   padding-top: 1px !important;
   padding-bottom: 1px !important;
 }

 menupopup#contentAreaContextMenu menupopup > menuitem,
 menupopup#contentAreaContextMenu menupopup > menu,
 #PlacesToolbar menupopup menupopup > menuitem,
 #PlacesToolbar menupopup menupopup > menu,
 menupopup#tabContextMenu menupopup > menuitem,
 menupopup#tabContextMenu menupopup > menu,
 menupopup.textbox-contextmenu > menuitem {
   font-size: 1em !important;
 }

 /* Menu Bar menus, text size to match macOS */
 toolbaritem#menubar-items menupopup > menuitem,
 toolbaritem#menubar-items menupopup > menu {
   font-size: 1.167em !important;
 }

 toolbaritem#menubar-items menupopup menupopup > menuitem,
 toolbaritem#menubar-items menupopup menupopup > menu {
   font-size: 1em !important;
 }

 /* Toolbar menu, LEFT/RIGHT padding fixes */
 #customization-toolbar-menu,
 toolbaritem#menubar-items menupopup,
 toolbaritem#menubar-items menupopup > menu > menupopup {
   padding-left: 2px !important;
   padding-right: 2px !important;
 }

 /* Context menu, TOP/BOTTOM padding fixes */
 #personal-bookmarks menupopup menuitem {
   padding-top: 1px !important;
   padding-bottom: 1px !important;
 }

 menupopup#contentAreaContextMenu menuitem,
 menupopup#contentAreaContextMenu menu {
   padding-top: 1px !important;
   padding-bottom: 1px !important;
 }

 menupopup#contentAreaContextMenu > .menuitem-iconic {
   padding-top: 0px !important;
   padding-bottom: 0px !important;
 }

 /* Menus, slightly adjust arrow */
 menupopup .menu-right {
   margin-right: 0px !important;
 }