refactor: ui structure refactoration

src/api/request.ts

src/app/page.tsx

src/components/ContentWrap/index.tsx

src/components/IntroArea/index.tsx

src/components/LinkButton/index.tsx

src/components/LinkButton/style.ts

src/components/PageTitleArea/index.tsx

src/components/PageTitleArea/style.ts

src/components/ScrollArea/index.tsx

src/components/ScrollArea/style.ts

src/components/StyleElements/index.tsx

src/components/StyleElements/style.ts

src/hooks/useBookInfo.ts

src/hooks/useScrollState.ts

src/style/App.style.ts