[INFRA] fix draft rendering css on mobile or when browser window is n…

…arrow (#889)

* sty: fix draft rendering css

* try md-sidebar

* try nav__title

* try [for=__drawer]

* try set color via :root instead

* try conditional css and do not accept overrides

* better style and comment

src/css/watermark.css

@@ -1,3 +1,10 @@
+/* 76.1875em are based on stylesheets: https://github.com/squidfunk/mkdocs-material/tree/master/material/assets/stylesheets */
+@media screen and (max-width: 76.1875em) {
+    .md-nav__title[for=__drawer] {
+        background-color: #ff0000 !important;
+    }
+}
+
 .md-header {
     background-color: #ff0000;
 }