Responsive theme CSS

I am a beginner in web design, so maybe my perception for many of you, is a little silly.

What am I missing in the Hugo tutorial is an example of responsive CSS that any beginner could use eg. to create your own theme.

I can make a blog with Hugo, but it scares me to create from scratch a CSS style sheet.

Maybe someone has and could share?

Try Skeleton.

Thx a lot.
Which you recommend: Skeleton or maybe Purecss?

We’re straying off topic, but…

PureCSS is active and has documentation.