ReSpec light/dark mode did not respect user preference

[jenstrickland]

Description of problem

I had a page in my browser tabs and when I visited it today it rendered in dark mode, although my user settings were set to auto and it was 10:30 am. I reloaded the page hoping it was just a mix up, but it persisted in dark mode. I had to use the little panel to change it to light mode so that I could continue my work in the group.

URL to affected spec or repo:

https://w3c.github.io/sustainableweb-wsg/#provide-useful-notifications

What happened (e.g., it crashed)?:

See description

Expected behavior (e.g., it shouldn't crash):

See description

Optional, steps to reproduce:

1. ...

[AlexDawsonUK]

Note: I've been experimenting with this and there appears to be an inconsistency between Chrome and other browsers regarding if system settings are set to auto and the light/dark setting is set to auto.

• Firefox & Safari default to light mode.
• Chrome defaults to dark mode.

I'm unsure if there should be a set behavior for auto (as possibly this should be defined by the user agent) but to ensure the user preference is adhered to it does comply in auto mode if either system preferences are defined as light or dark when auto is in effect (tested across all three browsers on MacOS).

Edit: This issue only seems to be present in ReSpec tooling, upon export to HTML the behavior functions as expected.