about the class (css)

Kryonoglou

<header class="Hero DiscussionHero DiscussionHero--colored"

How I can change it with CSS?

Code like this have space inside the words (in class) and I can't do nothing..
I try hero.discussionHero.discussionHero--colored but doesn't work.. :/
I try Hero DiscussionHero DiscussionHero--colored but still nothing.. :/

How I can change that type of class?

Pollux

You don't change classes with CSS. However, you can change how these classes effect the appearance of your site by overriding the associated CSS with your custom CSS.

If you want to change the classes themselves, you need an extension.

Ralkage

What are you trying to accomplish exactly?

Justice

If you want to change that element, you need to use this class:.Hero.DiscussionHero.DiscussionHero--colored
The code would look like this:
.Hero.DiscussionHero.DiscussionHero--colored{
/CSS properties here/
}
The spaces in the class name are there because that element has more than one class.

clarkwinkelmann

Justice that ?

Also you don't need to specify all classes. The element has three classes, and you can get it by specifying any of them. Using multiple ones is only needed to add specificity to either not match unrelated elements or match a specific state (here for example the --colored version is likely only present under tags which have a color assigned, and .Hero is reused for non-discusson hero banners as well)

Justice

clarkwinkelmann
I dont know Flarum too well, so I though it'd be better to just specify all the classes to be sure I dont accidentally target other elements. Nonetheless, I think .Hero will probably be enough.