What should I start after fininshing CSS scripting?

Question

Any sort of help and guidance for what I could start next would be a great help!!

Answer 1

JavaScript, to make the website interactive.
Then, you could either do PHP for backend stuff, or if you want to make styling easier check out Sass (scss).

Answer 2

JavaScript and preprocessor

Answer 3

SCSS preprocessor, and some concept of writing CSS like BEM, OOCSS and so on.