Tags in CSS?

[coro]

Hey everyone

Just joined the forum
It's been a few years since I last did any programming in relation to HTML, CSS and JS. I've looked at a few templates to see how different developers plan and program their sites. My question is why in a CSS document would a developer place this:

"  article, aside, audio, canvas, command, datalist, details, embed, figcaption, figure, footer, header, hgroup, keygen, meter, nav, output, progress, section, source, video {
	display:block
}
mark, rp, rt, ruby, summary, time {
	display:inline
}"

I've heard that it's tags? But I don't understand it's purpose, sorry for the stupid question. Hope everyone's ok and thanks in advance!

[felgall]

They are proposed HTML 5 tags that not all browsers currently understand. By including those definitions in the CSS it becomes possible to use those tags in the HTML without the page breaking in the browsers that don't understand them.

[VIPStephan]

CSS has no tags, it has selectors, properties, and values, grouped in rules:

/* this is a comment and the line below is a CSS rule */
selector {property: value;}

The simplest selectors are element selectors. The selector h1 applies to all <h1> elements in the HTML document:

h1 {color: red;}

And if multiple element types should get a similar style, CSS selectors can be separated by commas: h1, p {color: red;} applies to all <h1> and <p> elements in the document.

So, in conclusion, what you posted above are all element selectors that apply to their respective HTML counterparts (in this case it’s mostly the new HTML 5 elements), like <article>, <aside>, <audio>, etc.

These quotes, however, are invalid and should not be there. But it might be that you’ve just put them there by accident.