/* ===== 全局重置 ===== */
        * {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
        font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        :root {
        --primary-color: #0ea5e9;
        --secondary-color: #06b6d4;
        --sidebar-bg: #1e293b;
        --text-muted: #94a3b8;
        --border-color: rgba(94, 234, 212, 0.2);
        --hover-color: #38bdf8;
        --card-bg: rgba(15, 23, 42, 0.7);
        --text-light: #e2e8f0;
        }
        html,
        body {
        height: 100%;
        overflow: hidden;
        background: #0f172a;
        color: var(--text-light);
        }
        body {
        display: flex;
        }
        /* ===== 左侧菜单 ===== */
        .sidebar {
        width: 260px;
        background: var(--sidebar-bg);
        border-right: 1px solid var(--border-color);
        display: flex;
        flex-direction: column;
        flex-shrink: 0;
        height: 100vh;
        overflow-y: auto;
        box-shadow: 4px 0 20px rgba(0, 0, 0, 0.3);
        z-index: 10;
        }
        .logo-container {
        padding: 24px 20px;
        border-bottom: 1px solid var(--border-color);
        display: flex;
        align-items: center;
        gap: 12px;
        }
        .logo {
        width: 40px;
        height: 40px;
        background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
        border-radius: 10px;
        display: flex;
        align-items: center;
        justify-content: center;
        font-size: 20px;
        color: #fff;
        font-weight: 700;
        }
        .logo-text {
        font-size: 1.4rem;
        font-weight: 700;
        background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
        -webkit-background-clip: text;
        background-clip: text;
        color: transparent;
        }
        .version {
        font-size: 0.75rem;
        color: var(--text-muted);
        margin-top: 2px;
        }
        .nav-menu {
        flex: 1;
        padding: 20px 0;
        }
        .nav-item {
        display: flex;
        align-items: center;
        padding: 14px 20px;
        margin: 4px 12px;
        border-radius: 10px;
        color: var(--text-muted);
        cursor: pointer;
        transition: all 0.3s ease;
        text-decoration: none;
        }
        .nav-item:hover {
        background: rgba(56, 189, 248, 0.1);
        color: var(--text-light);
        }
        .nav-item.active {
        background: linear-gradient(90deg, rgba(14, 165, 233, 0.2), transparent);
        color: var(--hover-color);
        border-left: 3px solid var(--hover-color);
        padding-left: 17px;
        }
        .nav-icon {
        width: 24px;
        margin-right: 14px;
        text-align: center;
        font-size: 18px;
        }
        .nav-text {
        font-size: 0.95rem;
        font-weight: 500;
        }
        .sidebar-footer {
        padding: 20px;
        border-top: 1px solid var(--border-color);
        font-size: 0.8rem;
        color: var(--text-muted);
        text-align: center;
        }
        /* ===== 右侧主区域（顶部 + iframe） ===== */
        .main-content {
        flex: 1;
        display: flex;
        flex-direction: column;
        height: 100vh;
        overflow: hidden;
        background: #0f172a;
        }
        /* ---- 顶部（保留） ---- */
        .header {
        padding: 20px 30px;
        background: var(--sidebar-bg);
        border-bottom: 1px solid var(--border-color);
        display: flex;
        justify-content: space-between;
        align-items: center;
        backdrop-filter: blur(10px);
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        flex-shrink: 0;
        }
        .page-title {
        font-size: 1.8rem;
        font-weight: 700;
        color: var(--text-light);
        }
        .page-subtitle {
        font-size: 0.9rem;
        color: var(--text-muted);
        margin-top: 4px;
        }
        .user-info {
        display: flex;
        align-items: center;
        gap: 12px;
        flex-shrink: 0;
        }
        .user-avatar {
        width: 40px;
        height: 40px;
        border-radius: 50%;
        background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
        display: flex;
        align-items: center;
        justify-content: center;
        color: #fff;
        font-weight: 700;
        }
        /* ---- iframe 容器 ---- */
        .iframe-wrapper {
        flex: 1;
        overflow: hidden;
        background: #0f172a;
        }
        .iframe-wrapper iframe {
        width: 100%;
        height: 100%;
        border: none;
        display: block;
        }
        /* ===== 响应式 ===== */
        @media (max-width: 768px) {
        .sidebar {
        width: 70px;
        }
        .logo-text,
        .nav-text,
        .version,
        .sidebar-footer {
        display: none;
        }
        .logo-container {
        justify-content: center;
        padding: 20px 10px;
        }
        .nav-item {
        justify-content: center;
        padding: 14px 10px;
        margin: 4px 8px;
        }
        .nav-icon {
        margin-right: 0;
        }
        .header {
        padding: 15px 20px;
        }
        .page-title {
        font-size: 1.2rem;
        }
        }
        @media (max-width: 480px) {
        .sidebar {
        width: 56px;
        }
        .logo {
        width: 32px;
        height: 32px;
        font-size: 16px;
        }
        .nav-item {
        padding: 10px 6px;
        margin: 2px 4px;
        }
        .nav-icon {
        font-size: 14px;
        }
        .header {
        padding: 10px 14px;
        flex-wrap: wrap;
        gap: 8px;
        }
        .page-title {
        font-size: 1rem;
        }
        .page-subtitle {
        font-size: 0.7rem;
        }
        .user-avatar {
        width: 30px;
        height: 30px;
        font-size: 12px;
        }
        }
        body {
        background-color: #0f172a;
        background-image: url('images/index_ditu.jpg');
        background-size: cover;
        background-position: center center;
        background-attachment: fixed;
        background-repeat: no-repeat;
        }