<label for="error">...</label>
<input class="error" type="text" id="error" />

<label for="warning">...</label>
<input class="warning" type="text" id="warning" />

<label for="success">...</label>
<input class="success" type="text" id="success" />

<label for="info">...</label>
<input class="info" type="text" id="info" />