Can you set a max and min width on a Form?

Right now, I have my Form nested in a <div>...
Code HTML4Strict:
<!-- ADD A COMMENT -->
	<div id="boxMainContent">
		<div id="boxAddComment">
			<h3>What Do You Think?</h3>
			<form id="addComment" action="" method="post">

...with these styles...

Code CSS:
	min-width: 340px;
	max-width: 580px;
	margin: 40px auto;
	padding: 0 30px 30px 30px;
	border: 1px solid #333;

If I can lose the extra layer, that would be great!