#pwpc-back-to-top{position: fixed; bottom: 40px; right: 40px; z-index: 9999; width: 32px; height: 32px; text-align: center; line-height: 30px; background: #000; color: #fff; cursor: pointer; border: 0; border-radius: 2px; text-decoration: none; transition: opacity 0.2s ease-out; opacity: 0;}
#pwpc-back-to-top:hover{background: #555; color:#fff;}
#pwpc-back-to-top.pwpc-ss-show{opacity: 1;}