Add GitBook theme structure with Traditional Chinese docs

gitbook/components/CategoryItem.js

@@ -0,0 +1,18 @@
+import SmartLink from '@/components/SmartLink'
+
+export default function CategoryItem ({ selected, category, categoryCount }) {
+  return (
+    <SmartLink
+      href={`/category/${category}`}
+      passHref
+      className={(selected
+        ? 'hover:text-white dark:hover:text-white bg-green-600 text-white '
+        : 'dark:text-green-400 text-gray-500 hover:text-white dark:hover:text-white hover:bg-green-600') +
+      ' flex text-sm items-center duration-300 cursor-pointer py-1 font-light px-2 whitespace-nowrap'}>
+
+      <div><i className={`mr-2 fas ${selected ? 'fa-folder-open' : 'fa-folder'}`} />{category} {categoryCount && `(${categoryCount})`}
+      </div>
+
+    </SmartLink>
+  );
+}