<div class="container">  
  <form id="contact" action="" method="post">
    <h3>Colorlib Contact Form</h3>
    <h4>Contact us for custom quote</h4>
    <fieldset>
      <input placeholder="Naam" type="text" tabindex="1" required autofocus>
    </fieldset>
    <fieldset>
      <input placeholder="e-mail" type="email" tabindex="2" required>
    </fieldset>
    <fieldset>
      <input placeholder="telefoonnummer (optioneel)" type="tel" tabindex="3" required>
    </fieldset>
    <fieldset>
      <input placeholder="website (optioneel)" type="url" tabindex="4" required>
    </fieldset>
    <fieldset>
      <textarea placeholder="Type je bericht hier..." tabindex="5" required></textarea>
    </fieldset>
    <fieldset>
      <button name="verzenden" type="submit" id="contact-submit" data-submit="...Sending">Submit</button>
    </fieldset>
    </form>
</div>