Unfortunately, Firefox does not have a built-in feature to allow sites colors on some sites and force your own preferred colors on other sites. There is an add-on for deciding on a tab-by-tab basis that you could test out. I haven't used it myself, but I use one of the developer's other add-ons:

https://addons.mozilla.org/firefox/addon/togglewebsitecolors/

Unfortunately, Firefox does not have a built-in feature to allow sites colors on some sites and force your own preferred colors on other sites. There is an add-on for deciding on a tab-by-tab basis that you could test out. I haven't used it myself, but I use one of the developer's other add-ons: https://addons.mozilla.org/firefox/addon/togglewebsitecolors/

Hi! Thank you for trying to help me!!! Unfortunately, I tried this extension and it's not very robust. Like, it doesn't remember when I turn it off for a specific website. I thought this was a pretty great feature at first, and was hoping it would really enhance my web browsing. But both the extension and the built-in browser feature have been of surprisingly little use due to their shortcomings.

The alternative is to find an add-on that lets you set colors for specific sites (by injecting style rules into the page to override the site's style rules).