.duan{width:700px;margin:20px auto 0 auto;border:0}.terminal{cursor:pointer;font-size:20px;line-height:60px;color:#666;height:60px;font-weight:600;text-align:center}.terminal.active{color:#000;border-bottom:4px solid #000;transition:background-color 1s;transition:all .5s ease}