feat(style): added dark mode (#446)

src/design-tokens/useLocalStorage.ts

@@ -0,0 +1,38 @@
+import { useState } from 'react';
+
+// based on https://usehooks.com/useLocalStorage/
+const useLocalStorage = <V>(key: string, initialValue: V) => {
+  // State to store our value
+  // Pass initial state function to useState so logic is only executed once
+  const [storedValue, setStoredValue] = useState(() => {
+    try {
+      // Get from local storage by key
+      const item = window.localStorage.getItem(key);
+      // Parse stored json or if none return initialValue
+      return item ? JSON.parse(item) : initialValue;
+    } catch (error) {
+      // If error also return initialValue
+      console.error('An error occurred getting a sessionStorage key', error);
+      return initialValue;
+    }
+  });
+
+  // Return a wrapped version of useState's setter function that ...
+  // ... persists the new value to localStorage.
+  const setValue = (value: V) => {
+    try {
+      // Allow value to be a function so we have same API as useState
+      const valueToStore = value instanceof Function ? value(storedValue) : value;
+      // Save state
+      setStoredValue(valueToStore);
+      // Save to local storage
+      window.localStorage.setItem(key, JSON.stringify(valueToStore));
+    } catch (error) {
+      console.error('An error occurred writing to sessionStorage', error);
+    }
+  };
+
+  return [storedValue, setValue];
+};
+
+export default useLocalStorage;