[feat]: ✨ add table style

[yoosion030]

Description

An intuitive UI was provided when the user added a table of contents:

If the viewport is less than 1,500px, it returns to its original position:

The following changes were made to add this function:

1. Create a .css file and add styling to the .notion-table-of-contents class
2. Import css file from _app.tsx

I've been using this feature on my branch for about 3 months, so it would be great to apply it to that branch too!
It's already being applied on my site. If you want to see it in person, it would be a good idea to access the link.

https://sion-log.vercel.app/next-14

PR Checklist

• I have read the Contributing Guide
• I have written documents and tests, if needed.

[vercel]

Someone is attempting to deploy a commit to a Personal Account owned by @morethanmin on Vercel.

@morethanmin first needs to authorize it.

[jungsikjeong]

오 좋네요..! 근데 다크모드일때 목차 색상이 잘안보이네요..
혹시 @morethanmin 님께서는 이런식으로 도입해주실 생각은없으실까요?ㅠㅠ

[morethanmin]

@jungsikjeong @yoosion030
개선하면서 같이 작업해보겠습니다~!

[morethanmin]

리뷰가 너무 늦어졌네요 죄송합니다 ㅠ,ㅠ

아래 내용이 고려되면 좋을 것 같습니다. 여유가 되신다면 작업해주셔도 좋고, 아니면 제가 이어서 작업하겠습니다~!

• 새로고침시 해당 content로 스크롤 되어야함
• darkmode 고려