Textarea nicht gleich groß mit Input-Länge

#formular {
color: #000;
background-color: #fff;
}


#formular input, textarea {
display: inline;
width: 15em;
float: left;
border: 1px solid #d8d8d8;
background-color: #d8d8d8;
margin: 5px;
padding: 2px;
}


#formular textarea {
width: 15em;
}


.submit, .reset {
background-color: #fff;
border: 3px solid #d8d8d8;
}


label {
width: 8em;
margin: 5px;
padding: 5px;
float: left;
text-align: right;
}


input, textarea {
border: 1px solid #d8d8d8; 
background: #fff; 
width: 90%;
}


input { 
font-size: 90%;
}

<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<style type="text/css"><!--
div {background: #146A55 top left no-repeat;
padding:1em;
width: 500px;
}
label, input, textarea {
float: left;
}
label {
clear: left;
width:100px;
}
input {
width: 230px;
}
textarea {
width: 343px;
}
form > div {
overflow: hidden;
}
label {
padding-top: .5em;
}
input, textarea {
margin-bottom: 1em;
}
--></style></head>
<body>
<form action="was auch immer.php" method="post">
<div>
<label for="name">Name</label>
<input type="text" name="name" id="name"/>
<label for="e-mail">E-Mail</label>
<input type="text" name="e-mail" id="e-mail"/>
<label for="homepage">Homepage</label>
<input type="text" name="homepage" id="homepage"/>
<label for="kommentar">Kommentar</label>
<textarea cols="30" rows="15" name="kommentar" id="kommmentar">
</textarea>
<input type="submit" value="Senden" id="senden">
</div>
</form>
</body>
</html>