.head {
    width: 500px;
    height: 200px;
    margin: 0 auto;
}

html {
    height: 100%;
    width: 100%;
    background: url("../img/bg-plain.jpg") repeat 50% 0;
    background-size: cover;
    background-color: #101010;
}

body {
    height: 100%;
    width: 100%;
    height: 100%;
    width: 100%;
    background: rgba(11, 11, 11, 0.1); /* 半透明 */
    backdrop-filter: blur(3px); /* 毛玻璃效果 */
}

.login {    
    border-radius: 15px;
    padding: 0 50px;
    position: relative;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    background-color: #282c3400;
}
.header {
    font-size: 38px;
    font-weight: bold;
    text-align: center;
    line-height: 200px;
    color: #61dafb;
}

span {
    display: block;
    font-size: 18px;
    color: #61dafb;
    text-align: center;
    margin-top: 5px;
    margin-bottom: 5px;
}