OK, but from a designer's perspective, you want to be careful with just inverting colours. The contrast is way too strong here from the demo you offered and the visited link 'purple' is already bleeding on black.

Have a read of an article such as this one, and be smart about colour translation. You might need to calculate contrast or offer a contrast setting as a minimum, and watch for shadows.

https://uxdesign.cc/turn-the-lights-off-designing-the-dark-m...

Side note: I've been really happy with the "Dark Reader" plugin on various browsers. Have a look at it and see how it handles brightness (+/-) and contrast (+/-).