userContent.css

@-moz-document url(about:home), url(about:newtab), url(about:privatebrowsing) {
     .click-target-container *, .top-sites-list * {
         color: #fff !important;
         text-shadow: 0px 4px 2px #000 !important;
    }
     body::before {
         content: "" ;
         z-index: -1 ;
         position: fixed ;
         top: 0 ;
         left: 0 ;
         /*make a folder for the image*/
         background: #f9a no-repeat url(img/OUTRUN-PC-4K.png) center ;
         /*make a folder for the image*/
         background-size: cover ;
         width: 100vw ;
         height: 100vh ;
    }
     *::selection {
         background: #f7a400 !important;
    }
     .top-site-outer .tile{
         background: #42414d !important;
         border: 2px solid #000000 !important;
         border-radius: 50px !important;
    }
     .top-site-outer .top-site-icon{
         background-color: #0000 !important;
    }
     .top-site-outer .title .icon {
         fill: #f00 !important;
    }
     .search-wrapper .logo-and-wordmark .logo{
         background: url("img/librefox.png") no-repeat !important;
         background-size: auto;
         box-shadow: black 0px 5px 5px;
         border: 2px solid #3967d5;
         border-radius: 50px;
         background-size: cover !important;
    }
     .top-site-outer .title .icon{
         fill: #f00 !important;
        ;
    }
     .search-wrapper .search-handoff-button, .search-wrapper input{
         border-radius:50px !important;
    }
     .click-target-container *, .top-sites-list *{
         text-shadow: 0px 4px 2px #000 !important;
    }
     .fake-editable{
         width: 50% !important;
    }
}