feat: Organize sidebar (#1834)

* chore: Flip chinese label in language select

* feat: Add settings to sidebar, organize secondary items to bottom

app/hooks/useWindowSize.js

@@ -0,0 +1,31 @@
+// @flow
+import { debounce } from "lodash";
+import * as React from "react";
+
+export default function useWindowSize() {
+  const [windowSize, setWindowSize] = React.useState({
+    width: undefined,
+    height: undefined,
+  });
+
+  React.useEffect(() => {
+    // Handler to call on window resize
+    const handleResize = debounce(() => {
+      // Set window width/height to state
+      setWindowSize({
+        width: window.innerWidth,
+        height: window.innerHeight,
+      });
+    }, 100);
+
+    // Add event listener
+    window.addEventListener("resize", handleResize);
+
+    // Call handler right away so state gets updated with initial window size
+    handleResize();
+
+    return () => window.removeEventListener("resize", handleResize);
+  }, []);
+
+  return windowSize;
+}