width: auto; min-width: 200px
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title></title>
<style type='text/css'>
p {
padding: 10px;
margin: 10px;
border: thin solid black;
width: auto;
min-width: 200px;
}
</style>
</head>
<body>
<p>
This is a test. This is a test.
</p>
</body>
</html>
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