weird sidebar offset in firefox

[bradcarnage]

Checklist

• [X] I have updated to the latest available Home Assistant version.
• [X] I have cleared the cache of my browser.
• [X] I have tried a different browser to see if it is related to my browser.
• [ ] I have tried reproducing the issue in safe mode to rule out problems with unsupported custom resources.

Describe the issue you are experiencing

• frontend viewed via firefox 127.0.2+linuxmint1+virginia has a bug where the sidebar takes up "double width"
• might be because the loading screen is still shown upon page load... :thinking:
• also... the frontend will "reload" every couple minutes. extremely annoying haha

Describe the behavior you expected

the UI to be normal

Steps to reproduce the issue

1. be a nerd and run Linux Mint 21.1 (vera)
2. use firefox 127.0.2+linuxmint1+virginia
3. clear cache and load home assistant UI

What version of Home Assistant Core has the issue?

2024.6.4

What was the last working version of Home Assistant Core?

No response

In which browser are you experiencing the issue with?

FF 127.0.2+linuxmint1+virginia

Which operating system are you using to run this browser?

Linux Mint 21.1

State of relevant entities

No response

Problem-relevant frontend configuration

No response

Javascript errors shown in your browser console/inspector

No response

Additional information

Loading data can be seen on bottom of page. UI will log you out or "reload" after 2 to 3 minutes.

[bradcarnage]

possibly related to #21184 ?