reorganize the code

components/readerpage/TOC.tsx

@@ -3,8 +3,8 @@ import Link from "next/link";
 
 export const TOC = (props: { data: TTOCItem[] }) => {
   return (
-    <div className="sticky top-[5em] mx-5 p-2 border-l border-dashed border-gray-500">
-      <div className="p-2 font-bold border-b border-gray-500">{"TABLE OF CONTENTS"}</div>
+    <div className="sticky top-[5em] mx-5 p-2 border-gray-500">
+      <div className="p-2 font-bold text-center border border-gray-500">{"TABLE OF CONTENTS"}</div>
       <ul className="flat-scrollbar my-1 px-1 h-[60vh] overflow-y-auto">
         {props.data?.map((item) => (
           <Link className="hover:text-sky-500" href={`#${item.anchorId}`} key={`toc-${item.anchorId}`}>