I thought I'd test it out on my laptop, as I usually go in on my phone. When I went to the site, it was in dark mode and difficult to read, as you said, so clicked the button and changed it to light mode. I then realised I wasn't actually logged in, and when I logged in, I noticed the button to change the light/dark setting had disappeared, which is strange. So Icarus, maybe try logging out to see if you can access the button for light/dark, because it may not be visible when you're logged in. Also, I use Firefox browser, so it may be different in other browsers. Hope this helps.