If you use FF searching Mozilla for HN reveals several extensions that may be useful. I use HN Enhance for dark mode viewing. https://addons.mozilla.org/en-US/firefox/search/?q=HN
The colour is configurable in your profile via the "topcolor" setting. Is it possible you've changed this from the default of #ff6600?
I’m confused… It’s always been the same color
#ff6600 for me
If you use FF searching Mozilla for HN reveals several extensions that may be useful. I use HN Enhance for dark mode viewing. https://addons.mozilla.org/en-US/firefox/search/?q=HN