🐛 No scrolling for Table of Contents if its too large

[kshpdr]

Issue description

When TOC gets too large, it gets cut off and can be seen only when a user scrolls to the very end of the title. Ideally, user should be able to hover on TOC and be able to scroll it separately from the main article.

Theme version

v2.7.6

Hugo version

hugo v0.120.4-f11bca5fec2ebb3a02727fb2a5cfb08da96fd9df+extended darwin/arm64

Which browser rendering engines are you seeing the problem on?

Chromium (Google Chrome, Microsoft Edge, Brave, Vivaldi, Opera, etc.)

URL to sample repository or website

https://tuberlin.ru/posts/cs/

Hugo output or build error messages

No response