title: modal appear behind fixed navbar
body: <p>so i have bootstrap based site with fixed navigation bar (that follow you around the page at the top) and when i want to show modal popup, it appear behind those navigation bar, how to fix?</p>
  
  <p>and i using <a href="https://graygrids.com/item/margo-free-multi-purpose-bootstrap-template/" rel="noreferrer">margo template from graygrids</a></p>
  
  <p>it also appear in summernote modals for uploading picture, so it looks like all modal will appear behind those navigation bar.</p>
  
  <p><a href="https://i.stack.imgur.com/mZy6x.png" rel="noreferrer"><img src="https://i.stack.imgur.com/mZy6x.png" alt="enter image description here"></a></p>