We don't think there is a need for this. There are lots of plugins for all the browsers nowadays that can make a dark mode out of any website, Macs have an overall dark UI, and Chrome is rolling out a dark UI that can be enabled in settings.
The extension may be enabled "per-site" but you may also use Chrome's Settings to limit access to specific sites if you wish some extra security. The "reverse color" effect is actually quite "eye-friendly".