Visual glitch causing top bar to shrink during search

[MrAnno]

Checklist

• I have read and accepted the contributing guidelines.

How did you create the site?

Built from jekyll-theme-chirpy

Describe the bug

The top bar shrinks by a few pixels when using the search bar.

Screencast_20250406_182602.webm

Steps To Reproduce

1. Focus the search bar
2. Write something into the search bar

The top bar will have an implicit flex-shrink: 1 property (at least in recent Firefox versions), causing it to shrink by 3 pixels, which results in some minimal ugly movement.

Expected Behavior

No movement/shaking.

Environment

• Ruby:
• Jekyll:
• Chirpy:

Anything else?

No response