JSFiddle - React, Tailwind, and code Playground
HTML
<form method="post" action="http://www.someurl.com/formHandler.php">
<fieldset>
<legend>Personal info</legend>
<label for="name">Name:</label>
<input type="text" id="name" class="text" />
<label for="email">Email</label>
<input type="text" id="email" class="text" />
</fieldset>
<fieldset>
<legend>Optional</legend>
<label for="info">Comments?</label>
<textarea id="info"></textarea>
<input type="submit" value="submit" class="submit" />
</fieldset>
</form>
CSS
form { display:block; background-color: #9e9e9e; padding: 20px; width: 540px; /*200 + 300 + (20 * 2)*/ }
legend { font-weight: bold; }
label { display: inline-block; width: 200px; float: left; clear: left; }
input { display: block; width: 300px; float: left; }
input.submit { margin:20px 0 0 200px; width: auto; }