I am no CSS expert, but this should get you started. Of course the styles should be in an external style sheet.
<html>
<head>
<style>
html {
font-size: 76%;
}
body {
font-size: 1.0em;
font-family: verdana;
}
div.input {
border: 1px solid white;
clear: left;
width: 25em;
height: 5em;
padding: 2px;
margin-bottom: 1.0em;
}
div.error {
border: 1px solid red;
}
div.label {
float: left;
width: 7em;
}
div.field {
float: left;
}
div.errormessage {
color: red;
}
div.description {
color: #bbb;
}
input.text {
width: 13em;
}
</style>
</head>
<body>
<form>
<div class="input error">
<div class="label">
<div> </div>
<label>First name:<br>(required)</label>
</div>
<div class="field">
<div class="errormessage">error message here</div>
<input type="text" name="FirstName" class="text">
<div class="description">optional description here</div>
</div>
</div>
<div class="input">
<div class="label">
<div> </div>
<label>Last name:<br>(required)</label>
</div>
<div class="field">
<div class="errormessage"> </div>
<input type="text" name="LastName" class="text">
<div class="description">optional description here</div>
</div>
</div>
</form>
</body>
</html>