.back-to-top{position:fixed;text-indent:-999em;background:#f3f3f3 url(data:image/svg+xml;base64,PHN2ZyBpZD0iRWJlbmVfMSIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIiB3aWR0aD0iMTcuNCIgaGVpZ2h0PSIxMC44IiB2aWV3Qm94PSIwIDAgMTcuNCAxMC44Ij48c3R5bGU+LnN0MHtmaWxsOiMyQTMxMzY7fTwvc3R5bGU+PHBhdGggY2xhc3M9InN0MCIgZD0iTTIgMTAuN2w2LjctNi42IDYuNyA2LjcgMi0yLTYuNy02LjdWMmwtMi0yTDAgOC43eiIvPjwvc3ZnPg==) center 50% no-repeat;border:1px solid rgba(0,0,0,0.75);border-radius:.1875em;height:40px;width:40px;bottom:5em;right:1em;opacity:.25;z-index:3000}.back-to-top:hover{opacity:1;background-position:center 45%}