[update] upgrade the reader page

components/mdx/H2.tsx

@@ -1,6 +1,6 @@
 const H2 = (props: JSX.IntrinsicElements["h2"]) => {
   return (
-    <h2 className={"caption-font scroll-mt-20"} id={props.id}>
+    <h2 className={"caption-font mt-6 mb-2 scroll-mt-20"} id={props.id}>
       {props.children}
     </h2>
   );