/* ========== 移动端适配 ========== */
@media screen and (max-width: 768px) {
    /* 导航栏 */
    .navbar { padding: 10px 15px !important; }
    .navbar .container { flex-wrap: wrap; gap: 10px; }
    .navbar .nav-links { display: none; position: absolute; top: 100%; left: 0; right: 0; background: inherit; flex-direction: column; padding: 15px; box-shadow: 0 4px 12px rgba(0,0,0,0.1); }
    .navbar .nav-links.show { display: flex; }
    .navbar .menu-toggle { display: block !important; background: none; border: none; font-size: 24px; cursor: pointer; padding: 5px; }
    
    /* 卡片网格 */
    .products-grid, .courses-grid, .related-grid { grid-template-columns: 1fr !important; }
    .stats-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .modules-grid { grid-template-columns: 1fr !important; }
    .charts-grid { grid-template-columns: 1fr !important; }
    
    /* 内容区 */
    .container { padding: 15px !important; }
    .card { padding: 15px !important; }
    
    /* 表单 */
    .form-row, .two-cols { flex-direction: column; }
    
    /* 按钮 */
    .btn { width: 100%; justify-content: center; }
    
    /* 字体 */
    h1 { font-size: 1.5rem !important; }
    h2 { font-size: 1.25rem !important; }
    h3 { font-size: 1.1rem !important; }
}

/* ========== 暗黑模式 ========== */
[data-theme="dark"] {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-card: #1f2937;
    --text-primary: #e5e7eb;
    --text-secondary: #9ca3af;
    --border-color: #374151;
    --shadow: 0 2px 8px rgba(0,0,0,0.3);
}

[data-theme="dark"] body {
    background: var(--bg-primary);
    color: var(--text-primary);
}

[data-theme="dark"] .card,
[data-theme="dark"] .stat-card,
[data-theme="dark"] .module-card,
[data-theme="dark"] .chart-card {
    background: var(--bg-card);
    border-color: var(--border-color);
}

[data-theme="dark"] .navbar {
    background: linear-gradient(135deg, #1f2937, #374151);
}

[data-theme="dark"] .form-group input,
[data-theme="dark"] .form-group textarea,
[data-theme="dark"] .form-group select {
    background: var(--bg-secondary);
    border-color: var(--border-color);
    color: var(--text-primary);
}

[data-theme="dark"] h1,
[data-theme="dark"] h2,
[data-theme="dark"] h3,
[data-theme="dark"] h4 {
    color: var(--text-primary);
}

[data-theme="dark"] p,
[data-theme="dark"] span,
[data-theme="dark"] div {
    color: var(--text-primary);
}

[data-theme="dark"] .module-stat {
    background: var(--bg-secondary);
}

/* 暗黑模式切换按钮 */
.theme-toggle {
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: linear-gradient(135deg, #667eea, #764ba2);
    border: none;
    color: white;
    font-size: 24px;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
    z-index: 9999;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.3s;
}

.theme-toggle:hover {
    transform: scale(1.1);
}

[data-theme="dark"] .theme-toggle {
    background: linear-gradient(135deg, #ffd700, #ffb347);
}