Should i learn css, html or both

Answer 1

You need both. one without the other is meaningless to learn

Answer 2

You need to learn both definitely. But, you will need to learn other languages to make your life easier. Nowadays no one write website by using HTML CSS directly anymore. You can Google "markdown jekyll" and find lot of cool stuff which make web development super fast and fun.
here is the website: www.jekyllrb.com

Answer 3

At first html, then CSS, you must known both, to made a modern web pages.

Answer 4

html for content - on its own will produce websites that looks like something from the 80's.
add css for style.
add javascript for interactions and behaviour.