Hallo Carsten
Wenn du experimentieren möchtest, dann mache es doch so:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="de">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<meta http-equiv="Content-Style-Type" content="text/html"/>
<link rel="stylesheet" type="text/css" href="styles.css"/>
<style type="text/css">
.textarea { background-color:red;
font-family:sans-serif;
border-style:1px solid blue;
color:yellow;
visibility:hidden}
.specialDiv { visibility:hidden;
display:none
}
</style>
<title>Titel</title>
</head>
<body style="background-color:magenta">
<h1>Heading</h1>
<form method="post" action="form.php">
<p>
<input type="hidden" name="subaction" value="edit_az"/>
<textarea cols="100" rows="10"
style="">
</textarea class="textarea">
</p>
<div class="specialDiv">
<p>Foo</p>
</div>
</form>
</body>
</html>
Dann kannst du das CSS auch ggf. in den Validator packen und - so du fertig bist - gleich in die CSS-Datei.
Herzliche Grüße
Wolfgang