Board Thread:Support Requests - Designing Your Wiki/@comment-4347751-20130719121512/@comment-1330470-20130719145758

Original Authority wrote: So id would cover one thing like background color?

That's not what I was saying. You are free to append as many rules (color, background-color, font-family, width, whatever) to a CSS selector, whether it's ID based, or Class based, or none at all. However if you have a page with  and then, later in the same page, have another , then your document is not valid and you may run into issues... while you are permitted as many   as you like.