Thanks for sending those pictures in! And that's okay - I'll do my best to guess at the possibilities.
Do you maybe have an extension added to your Chrome to turn on Dark Mode for certain sites (or Canvas specifically)? I see that there are quite a few, even just for Canvas (see this link of the Chrome Extension store), so if you have one of those on your device you may just need to turn it off momentarily to see if that fixes it.
If you don't have an extension, does your school happen to use a Website Accessibility tool? For example, my institution uses YuJa's website accessibility and it's embedded in every page in Canvas (see screenshot of an example). When you click on those tools, often they have "display" accessibility options, some of which may include a dark mode. If that's the case for you and it's currently turned on, you can typically use the tool to also turn that off and save the change until you are ready to use it again.
As a general question, about how long ago did you get that set up? A week, a day, a month, etc.? Another tip I'd recommend trying is to clear your Chrome cache for at least as far back as when you started seeing that. If the issue is related to just your browser settings, that should clear it up. If you need help with that, here's a support article that describes what to do for clearing Chrome's cache and selecting a certain time range.
I hope one of those helps you find what you need!