body {
    /* 原有样式保留，这里只新增登录遮罩和模态框的样式 */
    /* 全局遮罩层，未登录时阻止页面交互 */
 .login-mask {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    z-index: 9998;
    display: flex;
    justify-content: center;
    align-items: center;
}
/* 模态框 */
.qrcode-modal {
    width: 340px;
    background: #fff;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 5px 20px rgba(0,0,0,0.3);
    z-index: 9999;
}

    .qrcode-modal h3 {
        margin-top: 0;
        font-size: 20px;
    }

    .qrcode-modal img {
        width: 200px;
        height: 200px;
        margin: 10px auto;
        display: block;
        border: 1px solid #ddd;
    }

    .qrcode-modal .tip {
        color: #666;
        font-size: 14px;
        margin-top: 10px;
    }

    .qrcode-modal .close-btn {
        margin-top: 15px;
        background: #f0f0f0;
        border: none;
        padding: 6px 16px;
        border-radius: 4px;
        cursor: pointer;
    }
/* 退出登录按钮 */
.logout-btn {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: #dc3545;
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 30px;
    cursor: pointer;
    z-index: 10000;
    box-shadow: 0 2px 6px rgba(0,0,0,0.2);
}
/* 页面主要内容默认正常显示，但遮罩会盖住它并禁止交互 */
.main-content {
    position: relative;
}
/* 禁用页面滚动（遮罩出现时） */
body.modal-open {
    overflow: hidden;
}
}