fix: version switcher dropdown overflow on smaller screens (#578)

[Tanisha127]

Problem

Fixes #578

The version switcher dropdown extends beyond the viewport on smaller screens, making older versions (including "dev") unreachable.

As seen in the issue screenshot, even on a 21.5-inch screen the dropdown was already cut off. Maintainers temporarily trimmed switcher.json (PRs #602, #727, #843) as a workaround, but as more versions are released this problem will keep recurring.

Solution

Added a custom CSS file that permanently fixes the overflow by limiting the dropdown height to 60% of the viewport and enabling vertical scrolling — so all versions remain accessible on any screen size, regardless of how many versions are in switcher.json in the future.

Changes

• Added docs/source/_static/custom.css with overflow fix
• Registered the CSS file in docs/source/conf.py

Testing

• Built docs locally with sphinx-build -b html source build/html
• Verified scrolling works on small screens via Chrome DevTools device simulation (tested at 1280px, 768px, 375px widths)
• All versions visible and selectable on all screen sizes

[Tanisha127]

Hi @jonbrenas and @ahernank,

I've submitted a fix for this issue in PR #1271.
The fix adds a custom CSS file that limits the version switcher dropdown height to 60% of the viewport and enables vertical scrolling — so all versions remain accessible on any screen size, regardless of how many versions are in switcher.json in the future.
All 8 CI checks have passed including linting, coverage, and tests across Python 3.10, 3.11, and 3.12.
Would appreciate your review when you get a chance. Thanks!