Support TOC to automatically move position

[luckwyy]

Checklist

• I have read and accepted the contributing guidelines.

Is your feature request related to a problem? Please describe

When I open a blog on my computer, TOC (table of content) can be displayed normally on the right side of the webpage. However, if I open a blog on my phone, TOC is not displayed. If the blog is long, it is difficult to locate the desired content.

Describe the solution you'd like

If possible, I hope that when the webpage is displayed at a small screen size, the TOC can be displayed at the head of a blog post.

Describe alternatives you've considered

No response

Additional context

No response

[huanyushi]

This functionality is implemented on some webpages, such as Zhihu (a Chinese Q&A website). When we open it on a mobile device, its table of contents automatically appears at the top of the page. Perhaps we can refer to similar websites to see how they achieve this.