Dark Mode loading causes temporary unusable state for website

[Mobmaker55]

Observed/problematic behavior

Opening the website for the first time, the website loads as light mode (which is okay). Then, the website freezes, the content disappears, dark mode sets in (presumably read from my browser preferences? I didn't click anything), and then content reappears. This took about two seconds, which while minor, is still two seconds where the website is not usable.

Expected behavior

The website should either load dark mode assets in the first place, or at least keep items clickable and just load / unload stylesheets without completely re-loading page content.

Steps to reproduce

Make sure you have no cookies / site data, and no cache for the website (a "first time" user)
Have browser preferences include dark mode
Go to website

Other

No response