.frosted{
    display: flex;
    flex-direction: column;
    backdrop-filter: blur(25px);
    background: rgba(255, 255, 255, 0.3); /* 添加这一行 */
    /* 你可能需要为非支持backdrop-filter的浏览器添加一个备用方案 */
    -webkit-backdrop-filter: blur(20px);
}

body {
    background: url(/images/123.png) no-repeat center center fixed;
    background-size: cover;
}