水平居中并且高度自适应：

.btnBox {    position: absolute;    bottom: 0;    left: 0;    height: 10%;    box-sizing: border-box;    width: 100%;    border-top: 1px solid #333;    display: flex;    justify-content: center;    align-items: flex-start;}.btnBox a {    border: 1px solid #333;    padding: 8px 16px;    margin: 15px;    border-radius: 5px;    display: inline-block;}