.seekback{position:fixed;top:88px;left:12px;width:40px;height:40px;border-radius:50%;box-shadow:0 0 5px rgba(0,0,0,.3);font-size:32px;color:#1997ff;line-height:40px;font-weight:500;text-align:center;transition:all .3s;opacity:0;visibility:hidden}.seekbackshow{opacity:1;visibility:visible}.seekback:hover{background-color:rgba(73,141,197,.08)}