What version of starlight are you using?
0.30.2
What version of astro are you using?
5.0.8
What package manager are you using?
npm
What operating system are you using?
linux
What browser are you using?
chrome, firefox
Describe the Bug
When the site title or logo (or both) are long, they extend beyond the viewport resulting in the menu toggle appearing on top of it and also the search icon not being visible.
Desktop View

Mobile View - Actual

Mobile View - Expected

Additional Information
The menu button is positioned fixed which takes it out of the flow of flexbox when determining the available space for the header so flexbox thinks it has more space than it really does.
Link to Minimal Reproducible Example
https://stackblitz.com/edit/withastro-starlight-sdx36mum
Participation