const dropDown = document.getElementById("nav-bar-grey");
const navBarOpen = document.getElementById("new-drop-down-js");
dropDown.onclick = showNav
const closeButton = document.getElementById("closebtn");
closeButton.onclick = closeNav


function showNav (event) {
    navBarOpen.classList.toggle("nav-open");
  }

  function closeNav (event) {
    navBarOpen.classList.toggle("nav-close");
  }

<!--//mobile -->

<div class="background-about-mobile">
  <div class="white-bg-about">

    <h3>About.</h3>
    <div class="dash"> - </div>
    <h6>Who are we?</h6>

    <p class="about-text-mobile">We are a professional Carpet cleaning company that operates in the Leicestershire Region. Specialising in Carpet, Upholstery, hard floors, blinds and curtain cleaning fully insured, DBS Checked with 12 years plus experience.</p>
    <div class="dash"> - </div>
    <h6>What Services do we provide?</h6>

   <ul>
     <li>- Carpet cleaning</li>
     <li>- Rug cleaning</li>
     <li>- Stain removal</li>
     <li>- Amtico and Karndean maintenance</li>
     <li>- Hard Floor Maintence</li>
     <li>- Curtains and blinds cleaning.</li>
    </ul>


  </div>