title: Make navbar collapse/close on click
body: <p>i have trouble making the navbar on mobile devices collapse with my website. The problem only concerns the mobile version of the website.</p>
  
  <p>When I click on a menu button, the site scrolls to the correct point, but the navbar remains opened, which is annoying. I tried to give the UL LI elements the same class like the "back" button in the navbar, which can collapse the navbar, but this does not work :/..
  Could anyone show me how I can make the navigation bar close whenever a menu item is clicked?</p>
  
  <p>This is the website: </p>
  
  <p>Thanks a lot</p>