set tabs-navbar shadow size to 0px wherever tabs won't be atop of navbar

chrome/navbar_tabs_oneliner.css

@@ -32,7 +32,10 @@ urlbar_full_width.css is VERY MUCH recommended for Firefox 71+ because of new ur
   #urlbar-container{ min-width:unset !important }
 }
 
-#TabsToolbar{ margin-left: var(--uc-navigationbar-width); }
+#TabsToolbar{
+  margin-left: var(--uc-navigationbar-width);
+  --tabs-navbar-shadow-size: 0px;
+}
 #tabbrowser-tabs{ --tab-min-height: var(--uc-toolbar-height) !important; }
 
 /* This isn't useful when tabs start in the middle of the window */

chrome/navbar_tabs_oneliner_menu_buttons_on_right.css

@@ -36,7 +36,10 @@ Window controls will be all wrong without it
   #urlbar-container{ min-width:unset !important }
 }
 
-#TabsToolbar{ margin-left: var(--uc-navigationbar-width); }
+#TabsToolbar{
+  margin-left: var(--uc-navigationbar-width);
+  --tabs-navbar-shadow-size: 0px;
+}
 #tabbrowser-tabs{ --tab-min-height: var(--uc-toolbar-height) !important; }
 /* This isn't useful when tabs start in the middle of the window */
 .titlebar-placeholder[type="pre-tabs"],.titlebar-spacer[type="pre-tabs"]{ width:8px !important}

chrome/navbar_tabs_oneliner_tabs_on_left.css

@@ -42,6 +42,7 @@ Window controls will be all wrong without it
 }
 #TabsToolbar{
   margin-right: var(--uc-navigationbar-width);
+  --tabs-navbar-shadow-size: 0px;
 }
 #toolbar-menubar[autohide="true"] > .titlebar-buttonbox-container,
 #tabbrowser-tabs,

chrome/navbar_tabs_responsive_oneliner.css

@@ -24,7 +24,10 @@ See the above repository for updates as well as full license text. */
   :root[uidensity="compact"] #navigator-toolbox{ --uc-toolbar-height: 32px; }
   :root[uidensity="touch"] #navigator-toolbox{ --uc-toolbar-height: 40px; }
 
-  #TabsToolbar{ margin-left: var(--uc-navigationbar-width); }
+  #TabsToolbar{
+    margin-left: var(--uc-navigationbar-width);
+    --tabs-navbar-shadow-size: 0px;
+  }
   #tabbrowser-tabs{ --tab-min-height: var(--uc-toolbar-height) !important; }
   
   /* This isn't useful when tabs start in the middle of the window */

chrome/tabs_below_content.css

@@ -46,6 +46,7 @@ linux_gtk_window_control_patch.css
   bottom: 0;
   width: 100vw;
   height: var(--tab-min-height);
+  --tabs-navbar-shadow-size: 0px;
 }
 #TabsToolbar:hover{ z-index: 1 }
 

chrome/tabs_on_bottom.css

@@ -48,6 +48,7 @@ linux_gtk_window_control_patch.css
 #titlebar{
   -moz-box-ordinal-group: 2;
   -moz-appearance: none !important;
+  --tabs-navbar-shadow-size: 0px;
 }
 
 .titlebar-placeholder,