[Bug]: Sidebar content scrolls horizontally while Reference tab is selected

[mootari]

📝 Issue Description

At a viewport width below 1280px the active marker for the Reference tab overflows the sidebar container and causes horizontal scrolling:

📋 On which page(s) it occurs

https://docs.solidjs.com/

🤔 Expected Behavior

No horizontal scrollbar or scrolling.

👀 Current Behavior

A horizontal scrollbar shows.

🖥️ Browser

Chrome 150, Firefox 152

📄 Additional Information

No response