メインのCSSコードを変更するにはどうすればいいですか？

[Lilly (Lillian Louis)]

I have posted CSS help to you many times. please read the links that people provide you for information.

Search section like on Reddit?

If you are trying to learn to customize your forum, please take some time to learn some basics of themes, components and CSS. Alternatively, you can always post in marketplace for paid help to customize your forum.