* { margin: 0; padding: 0; box-sizing: border-box; } html { width: 100%; height: 100%; overflow: hidden; } body { position: fixed; left: 0; top: 0; width: 100%; height: 100%; } .main { width: 100%; height: 100%; background-repeat: no-repeat; background-size: 100% 100%; background-color: #f5f0e8; } .unfold { width: 100%; height: 100%; display: block; }