How can I make a black theme? please help.
While you are in the editor. You can go to the top right on the top nav bar, and click your profile icon, then on that list you should see an option called “Change theme”. That will switch your theme between the light and dark theme!
If you are using google, you can also use an extension like the following, to customise the css of any page and use any color for a selected part of the editor, or any font you would like to make it easier for you!