Who likes it when an application offers a DARK MODE option? I sure do, and I kind of get irritated when there isn't a dark theme option. That is why I was pleased to find a small tweak involving several browsers. I tested this with Brave mobile browser, Waterfox desktop, Chrome desktop, and Firefox Desktop. Neither Waterfox nor Firefox seems to work for me. Chrome works with Google search, as does Brave mobile browser. Just experiment a little bit and see if you can get it to work for you, and if Dark Mode is as desirable to you as it is to me; hip hip hooray!
As a precaution, it is recommended that you backup your browser and/or system [create a restore point or system image backup] before altering any experimental settings.
If done correctly, and it works for you, then you should see something like this when you land on Google Search...
Of course, there is also the Dark Reader extension for Firefox, and I am sure Chrome has its own extensions, like Turn Out the Lights. However, I prefer to use native solutions, when possible, for several good reasons:
1 - Less security vulnerability because of smaller attack surface
2 - less resource splitting and drain means quicker page load etc.
3 - Much better privacy-wise because of no extension with permissions
4 - Less GUI clutter