new file

chrome/autohide_toolbox.css

@@ -0,0 +1,27 @@
+/* Hide the whole toolbar area unless urlbar is focused or cursor is over the toolbar */
+/* Dimensions on non-Win10 OS probably needs to be adjusted */
+
+:root:not([inDOMFullscreen]){ margin-top: 6px }
+:root[sizemode="maximized"]:not([inDOMFullscreen]){ margin-top: 14px }
+#navigator-toolbox{
+  position: fixed !important;
+  background-color: var(--lwt-accent-color,black);
+  transition: transform 82ms 33ms linear, opacity 82ms 33ms linear !important;
+  transform-origin: top;
+  margin-top: -6px;
+}
+:root[sizemode="maximized"] > #navigator-toolbox{ margin-top: -6px }
+
+#navigator-toolbox,
+#navigator-toolbox > *{
+  width: 100vw;
+  -moz-appearance: none !important;
+  line-height: 0;
+}
+
+:root:not([customizing]) > #navigator-toolbox:not(:focus-within):not(:hover){
+  transform: rotateX(86deg);
+  opacity: 0;
+}
+
+#PersonalToolbar[collapsed]{ margin-block-end: -7px }