I meant text-align: center; as one item - I can't remember what it's called at the moment (declaration??), sorry! Obviously, if you want to style several things about your header, you'll use the semi-colon between them. And yes, you can combine several things if you want to style them the same way, just add a comma in between.

Say you want all the headers to be centered, but only h1 to have a bottom border and to be in uppercase.

h1, h2, h3, h4, h5, h6 {text-align: center}
h1 {border-bottom: solid 1px; text-transform: uppercase}

(Gosh, this makes me look like I'm presenting myself as some sort of an experts, which is so far from the truth!)