*{margin:0;padding:0}html,body{overflow:hidden}.webgl{position:fixed;top:0;left:0;outline:none}.button-class{position:fixed;background-color:#fff;border:none;color:#000;padding:1vmin 2vmin;text-align:center;text-decoration:none;display:inline-block;font-size:3vmin;font-family:Helvetica,Arial,sans-serif;bottom:4vmin;left:50%;transform:translate(-50%);cursor:pointer;border-radius:.5vmin}