Status Chart: Investigate Firefox dark mode

[StephanTLavavej]

Reported by @h-vetinari in #2975 (comment).

I need to figure out why #2975 isn't working for Firefox. check_css() attempts to call load_charts() immediately (unlike the earlier #2967), so my tentative guess is that regex.test(sheet.href) is failing.

[StephanTLavavej]

I'm unable to reproduce this with Firefox 103.0.1 on Windows 11:

[fsb4000]

It works for me on Windows 10

[NN---]

Works in Firefox iOS.

[h-vetinari]

I retried this again. This time it worked for me. Not sure what changes occurred in the meantime (but I'm pretty sure not even the browser got updated in the meantime; maybe I had been particularly unlucky with the http connection to download the style sheet extremely slowly...?)

[StephanTLavavej]

Very strange - perhaps some sort of caching? Anyways, thanks for reporting the issue, and I'm glad it went away! Let us know if it behaves weirdly again.