Remove padding from buttons in tabs toolbar

chrome/hide_tabs_with_one_tab.css

@@ -1,7 +1,6 @@
 /* Makes tabs toolbar items zero-height initially and sets enlarge them to fill up space equal to tab-min-height set on tabs */
 /* Firefox 65+ only */
 
-/* REMOVE ALL BUTTONS you can from the tabs toolbar or this won't work properly */
 
 :root[sizemode="normal"] #nav-bar{ --uc-window-drag-space-width: 20px }
 
@@ -11,6 +10,7 @@
 
 :root:not([customizing]) #tabbrowser-tabs .tabs-newtab-button,
 :root:not([customizing]) #tabs-newtab-button,
+:root:not([customizing]) #TabsToolbar-customization-target > .toolbarbutton-1,
 :root:not([customizing]) #TabsToolbar .titlebar-button{
   -moz-appearance: none !important;
   height: 0px;
@@ -19,6 +19,13 @@
   -moz-box-align: stretch;
   margin: 0 !important;
 }
+
+:root:not([customizing]) #TabsToolbar-customization-target > .toolbarbutton-1 > .toolbarbutton-icon{
+  padding-block: 0px !important;
+  max-height: 28px;
+  height: 20px !important
+}
+
 #tabbrowser-tabs .tabbrowser-tab{ height: var(--tab-min-height) }
 
 #tabbrowser-tabs .tabbrowser-tab[first-visible-tab="true"][last-visible-tab="true"]{
@@ -44,4 +51,4 @@
 }
 #nav-bar{
   border-inline: var(--uc-window-drag-space-width) solid var(--toolbar-bgcolor);
-}
+}