The 404 page in dark mode had a light colored background and light colored text in mobile. So it’s not possible to see the “404” text.
We had not caught this ahead of today, so appreciate you catching and spending the time to share this with us @spitfire-hash! I’ve added this to our backlog to address.
Hope you’re otherwise enjoying dark mode!
Just wanted to follow up and let you know that we shipped a fix for this last week. Thanks again for the feedback, @spitfire-hash!