Hidden labels

<p>
     <label for="first_name">
          First name
          <span class="error">Please enter your first name</span>
     </label>
     <input type="text" name="first_name" id="first_name">
</p>

.visuallyhidden {
    border: 0;
    clip: rect(0 0 0 0);
    height: 1px;
    width: 1px;
    margin: -1px;
    padding: 0;
    overflow: hidden;
    position: absolute;
}