* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
        }

        :root {
            --primary-white: #ffffff;
            --secondary-white: #f9f9f9;
            --accent-gray: #f0f0f0;
            --text-dark: #333333;
            --text-light: #666666;
            --border-color: #eaeaea;
            --shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
            --transition: all 0.3s ease;
            --primary-color: #4361ee;
            --secondary-color: #3a0ca3;
            --accent-color: #f72585;
            --success-color: #4cc9f0;
            --warning-color: #f8961e;
        }

        /* 深色模式 */
        .dark-theme {
            --primary-white: #1a1a1a;
            --secondary-white: #222222;
            --accent-gray: #333333;
            --text-dark: #f0f0f0;
            --text-light: #aaaaaa;
            --border-color: #444444;
            --shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
            --primary-color: #5a6ff0;
            --secondary-color: #4d1dc2;
            --accent-color: #ff4da6;
            --success-color: #6bd4f5;
            --warning-color: #ffb347;
        }

        body {
            background-color: var(--secondary-white);
            color: var(--text-dark);
            line-height: 1.6;
            transition: var(--transition);
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        /* 顶部导航 */
        header {
            background-color: var(--primary-white);
            box-shadow: var(--shadow);
            position: sticky;
            top: 0;
            z-index: 100;
            transition: var(--transition);
        }

        .navbar {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px 0;
        }

        .logo {
            font-size: 1.4rem;
            font-weight: 700;
            color: var(--text-dark);
            text-decoration: none;
            display: flex;
            align-items: center;
            transition: var(--transition);
        }

        .logo i {
            margin-right: 8px;
            color: var(--primary-color);
            transition: var(--transition);
        }

        .nav-links {
            display: flex;
            list-style: none;
            align-items: center;
        }

        .nav-links li {
            margin-left: 20px;
        }

        .nav-links a {
            text-decoration: none;
            color: var(--text-light);
            font-weight: 500;
            transition: var(--transition);
            position: relative;
            font-size: 0.95rem;
            white-space: nowrap;
        }

        .nav-links a:hover {
            color: var(--text-dark);
        }

        .nav-links a:after {
            content: '';
            position: absolute;
            bottom: -5px;
            left: 0;
            width: 0;
            height: 2px;
            background-color: var(--text-dark);
            transition: var(--transition);
        }

        .nav-links a:hover:after {
            width: 100%;
        }

        /* 主题切换 */
        .theme-toggle {
            display: flex;
            align-items: center;
            margin-left: 15px;
            cursor: pointer;
            padding: 6px 12px;
            border-radius: 30px;
            background-color: var(--accent-gray);
            transition: var(--transition);
            border: 1px solid var(--border-color);
            white-space: nowrap;
        }

        .theme-toggle:hover {
            background-color: var(--border-color);
        }

        .theme-icon {
            font-size: 1rem;
            margin-right: 6px;
            color: var(--text-light);
            transition: var(--transition);
        }

        .theme-text {
            color: var(--text-light);
            font-size: 0.85rem;
            font-weight: 500;
            transition: var(--transition);
        }

        /* 手机菜单按钮 */
        .mobile-menu-btn {
            display: none;
            background: none;
            border: none;
            font-size: 1.5rem;
            color: var(--text-light);
            cursor: pointer;
            padding: 5px;
            transition: var(--transition);
        }

        .mobile-menu-btn:hover {
            color: var(--text-dark);
        }

        /* 手机菜单 */
        .mobile-nav {
            display: none;
            background-color: var(--primary-white);
            box-shadow: var(--shadow);
            position: fixed;
            top: 70px;
            left: 0;
            right: 0;
            z-index: 99;
            padding: 20px;
            border-top: 1px solid var(--border-color);
        }

        .mobile-nav.active {
            display: block;
        }

        .mobile-nav-links {
            list-style: none;
            display: flex;
            flex-direction: column;
        }

        .mobile-nav-links li {
            margin-bottom: 15px;
        }

        .mobile-nav-links a {
            text-decoration: none;
            color: var(--text-light);
            font-weight: 500;
            font-size: 1.1rem;
            display: block;
            padding: 10px 0;
            border-bottom: 1px solid var(--border-color);
            transition: var(--transition);
        }

        .mobile-nav-links a:hover {
            color: var(--text-dark);
            padding-left: 10px;
        }

        .mobile-theme-toggle {
            display: flex;
            align-items: center;
            justify-content: center;
            margin-top: 20px;
            padding: 12px;
            border-radius: 30px;
            background-color: var(--accent-gray);
            color: var(--text-light);
            font-weight: 500;
            cursor: pointer;
            transition: var(--transition);
            border: 1px solid var(--border-color);
        }

        .mobile-theme-toggle:hover {
            background-color: var(--border-color);
        }

        .mobile-theme-icon {
            margin-right: 8px;
            font-size: 1.1rem;
        }

        /* 主标题区 */
        .hero {
            padding: 60px 0 40px;
            text-align: center;
            background-color: var(--primary-white);
            margin-bottom: 40px;
            border-radius: 0 0 10px 10px;
            box-shadow: var(--shadow);
            transition: var(--transition);
        }

        .hero h1 {
            font-size: 2.2rem;
            margin-bottom: 15px;
            color: var(--text-dark);
            transition: var(--transition);
        }

        .hero p {
            font-size: 1.1rem;
            color: var(--text-light);
            max-width: 700px;
            margin: 0 auto 30px;
            transition: var(--transition);
        }

        /* 公告控制区域 */
        .announcement-controls {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            align-items: center;
            margin: 30px 0;
            gap: 15px;
            padding: 25px;
            background-color: var(--primary-white);
            border-radius: 10px;
            box-shadow: var(--shadow);
            transition: var(--transition);
        }

        .search-box {
            flex: 1;
            min-width: 300px;
            position: relative;
        }

        .search-box input {
            width: 100%;
            padding: 12px 20px 12px 45px;
            border-radius: 30px;
            border: 1px solid var(--border-color);
            background-color: var(--primary-white);
            color: var(--text-dark);
            font-size: 0.95rem;
            outline: none;
            transition: var(--transition);
        }

        .search-box i {
            position: absolute;
            left: 15px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--text-light);
            transition: var(--transition);
        }

        .categories {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
        }

        .category-btn {
            padding: 8px 16px;
            border-radius: 20px;
            background-color: var(--primary-white);
            border: 1px solid var(--border-color);
            color: var(--text-dark);
            cursor: pointer;
            font-size: 0.85rem;
            transition: var(--transition);
        }

        .category-btn:hover {
            background-color: var(--accent-gray);
        }

        .category-btn.active {
            background-color: var(--primary-color);
            color: white;
            border-color: var(--primary-color);
        }

        /* 公告网格 */
        .announcements-section {
            padding: 50px 0;
            background-color: var(--primary-white);
            border-radius: 10px;
            box-shadow: var(--shadow);
            margin-bottom: 40px;
            transition: var(--transition);
        }

        .section-title {
            text-align: center;
            margin-bottom: 40px;
        }

        .section-title h2 {
            font-size: 1.8rem;
            margin-bottom: 15px;
            color: var(--text-dark);
            transition: var(--transition);
        }

        .section-title p {
            color: var(--text-light);
            max-width: 600px;
            margin: 0 auto;
            transition: var(--transition);
            font-size: 0.95rem;
        }

        .announcements-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
            gap: 25px;
        }

        .announcement-card {
            background-color: var(--primary-white);
            border-radius: 10px;
            overflow: hidden;
            box-shadow: var(--shadow);
            transition: var(--transition);
            border: 1px solid var(--border-color);
            cursor: pointer;
        }

        .announcement-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
        }

        .dark-theme .announcement-card:hover {
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
        }

        .card-header {
            padding: 25px 25px 15px;
            border-bottom: 1px solid var(--border-color);
        }

        .card-category {
            display: inline-block;
            padding: 4px 12px;
            border-radius: 15px;
            font-size: 0.75rem;
            font-weight: 600;
            margin-bottom: 15px;
        }

        .category-important {
            background-color: rgba(247, 37, 133, 0.15);
            color: var(--accent-color);
        }

        .category-update {
            background-color: rgba(76, 201, 240, 0.15);
            color: var(--success-color);
        }

        .category-general {
            background-color: rgba(248, 150, 30, 0.15);
            color: var(--warning-color);
        }

        .card-title {
            font-size: 1.3rem;
            font-weight: 600;
            margin-bottom: 10px;
            color: var(--text-dark);
            transition: var(--transition);
        }

        .card-content {
            padding: 20px 25px;
            color: var(--text-light);
            font-size: 0.95rem;
            transition: var(--transition);
        }

        .card-footer {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 20px 25px;
            background-color: var(--accent-gray);
            font-size: 0.8rem;
            color: var(--text-light);
            transition: var(--transition);
        }

        .card-date {
            display: flex;
            align-items: center;
            gap: 5px;
        }

        .card-priority {
            display: flex;
            align-items: center;
            gap: 5px;
        }

        .priority-high {
            color: #ff4757;
        }

        .priority-normal {
            color: #2ed573;
        }

        /* 公告统计区 */
        .stats-section {
            padding: 50px 0;
            background-color: var(--primary-white);
            border-radius: 10px;
            box-shadow: var(--shadow);
            margin-bottom: 40px;
            transition: var(--transition);
        }

        .stats-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 30px;
        }

        .stat-item {
            text-align: center;
            padding: 25px 15px;
            border-radius: 10px;
            background-color: var(--secondary-white);
            transition: var(--transition);
        }

        .stat-item:hover {
            background-color: var(--accent-gray);
        }

        .stat-number {
            font-size: 2.2rem;
            font-weight: 700;
            color: var(--text-dark);
            margin-bottom: 10px;
            transition: var(--transition);
        }

        .stat-label {
            color: var(--text-light);
            font-weight: 500;
            transition: var(--transition);
            font-size: 0.95rem;
        }

        /* 页脚 */
        footer {
            background-color: var(--primary-white);
            padding: 40px 0 25px;
            margin-top: 50px;
            border-top: 1px solid var(--border-color);
            transition: var(--transition);
        }

        .footer-content {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            margin-bottom: 40px;
        }

        .footer-column {
            flex: 1;
            min-width: 250px;
            margin-bottom: 30px;
        }

        .footer-column h3 {
            font-size: 1.2rem;
            margin-bottom: 20px;
            color: var(--text-dark);
            transition: var(--transition);
        }

        .footer-column p {
            color: var(--text-light);
            margin-bottom: 20px;
            max-width: 300px;
            transition: var(--transition);
            font-size: 0.95rem;
        }

        .footer-links {
            list-style: none;
        }

        .footer-links li {
            margin-bottom: 10px;
            display: flex;
            align-items: center;
        }

        .footer-links i {
            margin-right: 10px;
            color: var(--text-light);
            width: 20px;
            transition: var(--transition);
        }

        .footer-links a, .footer-links span {
            color: var(--text-light);
            text-decoration: none;
            transition: var(--transition);
            font-size: 0.95rem;
        }

        .footer-links a:hover {
            color: var(--text-dark);
        }

        .social-links {
            display: flex;
            gap: 15px;
            margin-top: 15px;
        }

        .social-links a {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 40px;
            height: 40px;
            background-color: var(--accent-gray);
            color: var(--text-light);
            border-radius: 50%;
            transition: var(--transition);
        }

        .social-links a:hover {
            background-color: var(--text-dark);
            color: var(--primary-white);
        }

        .copyright {
            text-align: center;
            padding-top: 25px;
            border-top: 1px solid var(--border-color);
            color: var(--text-light);
            font-size: 0.85rem;
            transition: var(--transition);
        }

        /* 响应式设计 */
        @media (max-width: 992px) {
            .logo {
                font-size: 1.3rem;
            }
            
            .nav-links a {
                font-size: 0.9rem;
            }
            
            .nav-links li {
                margin-left: 15px;
            }
            
            .theme-toggle {
                padding: 5px 10px;
                margin-left: 10px;
            }
            
            .theme-text {
                font-size: 0.8rem;
            }
        }

        @media (max-width: 768px) {
            .navbar {
                padding: 12px 0;
            }
            
            .logo {
                font-size: 1.2rem;
            }
            
            .nav-links {
                display: none;
            }
            
            .mobile-menu-btn {
                display: block;
            }
            
            .hero {
                padding: 50px 0 30px;
            }
            
            .hero h1 {
                font-size: 1.8rem;
                margin-top: 20px;
            }
            
            .hero p {
                font-size: 1rem;
                padding: 0 10px;
            }
            
            .announcements-grid {
                grid-template-columns: 1fr;
            }
            
            .announcement-controls {
                flex-direction: column;
                align-items: stretch;
            }
            
            .search-box {
                min-width: 100%;
            }
            
            .categories {
                justify-content: center;
            }
            
            .section-title h2 {
                font-size: 1.6rem;
            }
            
            .section-title p {
                font-size: 0.9rem;
                padding: 0 10px;
            }
            
            .announcements-section, .stats-section {
                padding: 40px 0;
            }
            
            .stats-grid {
                grid-template-columns: repeat(2, 1fr);
                gap: 20px;
            }
            
            .stat-item {
                padding: 20px 10px;
            }
            
            .stat-number {
                font-size: 1.8rem;
            }
            
            .footer-column {
                flex: 100%;
                min-width: 100%;
            }
        }

        @media (max-width: 480px) {
            .hero h1 {
                font-size: 1.5rem;
            }
            
            .hero p {
                font-size: 0.95rem;
            }
            
            .stats-grid {
                grid-template-columns: 1fr;
            }
            
            .section-title h2 {
                font-size: 1.4rem;
            }
            
            .announcement-card {
                margin: 0 10px;
            }
            
            .card-header, .card-content, .card-footer {
                padding: 15px 20px;
            }
            
            .card-title {
                font-size: 1.2rem;
            }
            
            .footer-column h3 {
                font-size: 1.1rem;
            }
        }