I have a chrome addon that somehow makes the task bar black and also the google starting page but nothing else

actually it's just a theme...

i thought they were busy with it...

There are browser add ons that let you override the CSS for websites, so in theory you could make your own night mode for google.com

I know CSS... can you tell me what extension I need?

if possible for chrome and safari...

It's been a while since I used them, probably 10 years ago before Chrome existed and when Firefox wasn't on version 518.

Never used it but Stylebot looks like it should do what you want.
https://chrome.google.com/webstore/detail/stylebot/oiaejidbmkiecgbjeifoejpgmdaleoha?hl=en