bklick on "Adding Margin Moves Element and Dumps Content"

Hi,

I'm trying to spiff up this site: http://ramen-empire.com/ - using InkBlot theme with Webcomic plugin. Love both. =)

When I do this:

main, #sidebar1, #sidebar2 {
	border:1px solid;
	border-radius:15px;
	margin-right:2px;
	margin-left:2px;
	margin-top: 0;
	margin-bottom: 0;
}

Then sidebar1 vanishes. (Sidebar2 is empty right now, so maybe it does, too.)

(I have the code commented out right now. I think you can see what I mean with F12 in Chrome, though.)

What I want is a border around main and both sidebars that neither hugs the text or the wall of the page. I can't quite put my finger on why it's behaving this way.

Thanks for any help you all might offer!

Bart