/* 广场页面专用样式 */

    body {
        margin: 0;
        padding: 0;
        font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
        background: #f5f7fa;
        min-height: 100vh;
        overflow-x: hidden;
    }

    .container {
        min-height: 100vh;
        display: flex;
        flex-direction: column;
        width: 100%;
        overflow-x: hidden;
    }

    /* 导航栏样式 */
    .main-nav {
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(10px);
        border-bottom: 1px solid rgba(0, 0, 0, 0.1);
        position: sticky;
        top: 0;
        z-index: 1000;
        box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
        width: 100%;
    }

    .nav-container {
        width: 100%;
        padding: 0 20px;
        display: flex;
        align-items: center;
        justify-content: space-between;
        height: 64px;
        box-sizing: border-box;
    }

    .nav-brand {
        display: flex;
        align-items: center;
        gap: 12px;
    }

    .nav-logo {
        height: 32px;
        width: auto;
    }

    .brand-name {
        font-size: 18px;
        font-weight: 600;
        color: #1a1a1a;
    }

    .nav-menu {
        display: flex;
        gap: 8px;
    }

    .nav-item {
        padding: 8px 20px;
        color: #666;
        text-decoration: none;
        font-size: 15px;
        font-weight: 500;
        border-radius: 8px;
        transition: all 0.2s ease;
        position: relative;
    }

    .nav-item:hover {
        color: #333;
        background: rgba(0, 0, 0, 0.04);
    }

    .nav-item.active {
        color: #2563eb;
        background: rgba(37, 99, 235, 0.08);
    }

    .nav-user {
        display: flex;
        align-items: center;
        gap: 12px;
    }

    /* 广场头部 */
    .plaza-header {
        text-align: center;
        padding: 40px 20px;
        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
        color: white;
        width: 100%;
        box-sizing: border-box;
    }

    .plaza-header h1 {
        font-size: 32px;
        font-weight: 700;
        margin: 0 0 12px 0;
    }

    .plaza-subtitle {
        font-size: 16px;
        opacity: 0.9;
        margin: 0;
    }

    /* 主内容区 */
    .plaza-main {
        flex: 1;
        width: 100%;
        padding: 40px 20px;
        box-sizing: border-box;
        overflow-y: auto;
    }

    /* PPT网格布局 */
    .ppt-grid {
        display: grid;
        grid-template-columns: repeat(4, 1fr);
        gap: 24px;
        width: 100%;
        max-width: 1600px;
        margin: 0 auto;
    }

    /* PPT卡片 */
    .ppt-card {
        position: relative;
        background: white;
        border-radius: 12px;
        overflow: hidden;
        box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
        transition: all 0.3s ease;
        cursor: pointer;
    }

    .ppt-card:hover {
        transform: translateY(-4px);
        box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
    }

    .ppt-preview {
        position: relative;
        width: 100%;
        padding-bottom: 56.25%; /* 16:9 比例 */
        background: #f5f5f5;
        overflow: hidden;
    }

    .ppt-preview iframe {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        border: none;
        pointer-events: none;
        transform: scale(0.25);
        transform-origin: top left;
        width: 400%;
        height: 400%;
    }

    /* 确保iframe加载时有加载指示器 */
    .ppt-preview::before {
        content: '';
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
        width: 30px;
        height: 30px;
        border: 3px solid #f3f3f3;
        border-top: 3px solid #2563eb;
        border-radius: 50%;
        animation: spin 1s linear infinite;
        z-index: 1;
    }

    .ppt-preview.loaded::before {
        display: none;
    }

    





    /* 加载状态 */
    .loading-state {
        text-align: center;
        padding: 80px 20px;
    }

    .loading-spinner {
        width: 40px;
        height: 40px;
        margin: 0 auto 20px;
        border: 3px solid #f3f3f3;
        border-top: 3px solid #2563eb;
        border-radius: 50%;
        animation: spin 1s linear infinite;
    }

    @keyframes spin {
        0% { transform: rotate(0deg); }
        100% { transform: rotate(360deg); }
    }

    /* 空状态 */
    .empty-state {
        text-align: center;
        padding: 80px 20px;
    }

    .empty-icon {
        width: 80px;
        height: 80px;
        margin: 0 auto 20px;
        color: #d1d5db;
    }

    .empty-text {
        font-size: 18px;
        color: #666;
        margin-bottom: 24px;
    }

    .create-btn {
        display: inline-flex;
        align-items: center;
        gap: 8px;
        padding: 12px 24px;
        background: #2563eb;
        color: white;
        text-decoration: none;
        border-radius: 8px;
        font-weight: 500;
        transition: all 0.2s ease;
    }

    .create-btn:hover {
        background: #1d4ed8;
        transform: translateY(-1px);
    }

    /* 预览模态框 */
    .preview-modal {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        z-index: 2000;
        display: flex;
        align-items: center;
        justify-content: center;
    }

    .preview-modal.hidden {
        display: none;
    }

    .modal-overlay {
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(0, 0, 0, 0.6);
    }

    .modal-content {
        position: relative;
        width: 90%;
        max-width: 1200px;
        height: 90vh;
        background: white;
        border-radius: 12px;
        overflow: hidden;
        display: flex;
        flex-direction: column;
    }

    .modal-header {
        display: flex;
        align-items: center;
        justify-content: space-between;
        padding: 16px 24px;
        border-bottom: 1px solid #e5e7eb;
    }

    .modal-header h2 {
        font-size: 20px;
        font-weight: 600;
        color: #1a1a1a;
    }

    .modal-actions {
        display: flex;
        gap: 12px;
    }

    .action-btn,
    .close-btn {
        display: flex;
        align-items: center;
        gap: 6px;
        padding: 8px 16px;
        background: transparent;
        border: 1px solid #e5e7eb;
        border-radius: 6px;
        cursor: pointer;
        font-size: 14px;
        color: #666;
        transition: all 0.2s ease;
    }

    .action-btn:hover {
        background: #f9fafb;
        color: #333;
    }

    .close-btn:hover {
        background: #fee;
        border-color: #fcc;
        color: #e11;
    }

    .preview-frame {
        flex: 1;
        width: 100%;
        border: none;
    }

    /* 加载更多提示 */
.loading-more {
    text-align: center;
    padding: 40px 20px;
    color: #666;
}

.loading-more .loading-spinner {
    width: 30px;
    height: 30px;
    margin: 0 auto 10px;
    border: 3px solid #f3f3f3;
    border-top: 3px solid #2563eb;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

/* 页脚样式 */
footer {
    background: #f8f9fa;
    border-top: 1px solid #e5e7eb;
    padding: 20px;
    text-align: center;
    color: #666;
    font-size: 14px;
}

    /* 响应式设计 */
    @media (max-width: 1400px) {
        .ppt-grid {
            grid-template-columns: repeat(3, 1fr);
        }
    }

    @media (max-width: 1024px) {
        .ppt-grid {
            grid-template-columns: repeat(2, 1fr);
        }
    }

    @media (max-width: 768px) {
        .nav-menu {
            display: none;
        }
        
        .plaza-header h1 {
            font-size: 24px;
        }
        
        .plaza-subtitle {
            font-size: 14px;
        }
        
        .ppt-grid {
            grid-template-columns: 1fr;
            gap: 16px;
        }
        
        .modal-content {
            width: 100%;
            height: 100%;
            border-radius: 0;
        }
    }