Custom Icons on the Specific navigation Menu

Site URL: https://democrp.squarespace.com/

Hello team, I want to change the Navigation text to Icon. In the demo website, The About menu will be changed to icon.

You can use this password to access this site : 123456

Add to Cover Page Header

<style>
  li a[href="/about"] {
    background-image: url(https://cdn.pixabay.com/photo/2017/09/30/01/16/kitten-2801007__340.jpg);
    color: transparent !important;
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center center;
}
</style>

Ok, Its Working on cover page. How can I enable this feature on all pages?

Add this to Design > Custom CSS

  .nav-item a[href="/about"] {
    background-image: url(https://cdn.pixabay.com/photo/2017/09/30/01/16/kitten-2801007__340.jpg);
    color: transparent !important;
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center center;
}