Why does Safari sidebar change colour in MacOS Tahoe? How do I stop it?

My Safari sidebar in OS Tahoe keeps changing colour to match the website I am visiting. That's crazy. It's like your car's speedometer and controls changing colour every time you drive into a new location. The navigation side bar is supposed to be CONSISTENT no matter where you are visiting. I tried to remove the option under Safari Settings (see attachment) but it keeps tinting my sidebar. Any advice would be greatly appreciated.

[Edited by Moderator]