fix: Improved mobile styling

fix: Severla context menus miss-positioned
fix: Search filters not large enough on mobile
fix: Deep black background on mobile to match native apps
fix: Sticky document header allowing horizontal scrolling on mobile

app/hooks/useMediaQuery.js

@@ -0,0 +1,20 @@
+// @flow
+import { useState, useEffect } from "react";
+
+export default function useMediaQuery(query: string): boolean {
+  const [matches, setMatches] = useState<boolean>(false);
+
+  useEffect(() => {
+    const media = window.matchMedia(query);
+    if (media.matches !== matches) {
+      setMatches(media.matches);
+    }
+    const listener = () => {
+      setMatches(media.matches);
+    };
+    media.addListener(listener);
+    return () => media.removeListener(listener);
+  }, [matches, query]);
+
+  return matches;
+}