Docs: Search box is too small.

**Describe the bug**
The search box is now effectively a button - but with badly formatted text.  See the left nav of https://remix-ide.readthedocs.io

<img width="398" alt="Image" src="https://github.com/user-attachments/assets/f258f4c3-b3eb-42e1-b7c4-7375a1035c5d" />
