body {
    margin: 0;
    padding: 0;
    background-image: url('img.jpg');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    z-index: -1; /* 将 z-index 设置为 0 或其他正值 */
    position: relative; /* 确保 z-index 生效 */
}

.frosted-glass-effect {
    margin: 20px auto;
    width: 80%;
    padding: 20px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.18);
    z-index: -2; /* 确保元素在 body 元素之上 */
    position: relative; /* 确保 z-index 生效 */
}