Version dropdown breaks positioning of README

[trueberryless]

Describe the bug

When I extend a large list of versions in the sidebar, the README suddenly moves very far down, alto it should be sticky and always visible, no matter where the user scrolls.

To repro, follow these steps:

1. Go to https://main.npmx.dev/package/astro
2. Click on this dropdown menu (you can find it in the right column, right above the dependencies section):
   
3. Watch the README go brrrrrrrrrrrrrrrrrrrr 🚀

Additional context

No response

Logs

[MathurAditya724]

This looks similar to #2190

[ghostdevv]

This does seem to have been fixed by #2190!