I've tried putting
/*Firefox Focus*/ .mdl-slider:focus::-moz-range-thumb { box-shadow: 0 0 0 10px rgba(140,0,0,.26) !important; } /*Chrome Focus*/ .mdl-slider:focus::-webkit-slider-thumb{-webkit-box-shadow:0 0 0 10px rgba(153,204,255,.26); box-shadow:0 0 0 10px rgba(140,0,0,.26) !important; } /*FireFox*/ .mdl-slider::-moz-range-thumb { background: rgb(255,0,0) !important; } .mdl-slider::-moz-range-progress { background: rgb(255,0,0) !important; } .emby-slider { color: red !i