Why this RE in CSS dont work in theme.css

[Dio_Brando]

I’m using relearn theme. I put this code in the css theme.css

a[href~='/[^/]+/[^/]+/'] {
    background-color: red;
}

Why don’t want work? Hugo work in a different way?
I want select all a with 2 / in the string of href.

[jmooring]

@Dio_Brando

Hugo work in a different way?

Hugo has nothing to do with this.

@Dio_Brando

Why don’t want work?

Because you can’t use a regex expression in an attribute selector.

You probably want something like this:

a[href*="//"]

See docs:
https://developer.mozilla.org/en-US/docs/Web/CSS/Attribute_selectors#syntax