* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Microsoft YaHei', 'PingFang SC', sans-serif;
            line-height: 1.6;
            color: #333;
            background: #fff;
            transition: background 0.3s, color 0.3s;
        }

        /* ======================================== */
        /* 暗色模式 - 全局覆盖 */
        /* ======================================== */
        body.dark-mode {
            background: #0f0f1a;
            color: #ddd;
        }
        body.dark-mode .section-title {
            color: #e0e0ff;
        }
        body.dark-mode .section-subtitle {
            color: #888;
        }
        body.dark-mode .about-text {
            color: #bbb;
        }
        body.dark-mode .about-img-caption {
            color: #aaa;
        }
        body.dark-mode .recruit-section {
            background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
        }
        body.dark-mode .recruit-card {
            background: #1e1e3a;
            color: #ddd;
        }
        body.dark-mode .recruit-card p {
            color: #aaa;
        }
        body.dark-mode .work-card {
            background: #1e1e3a;
        }
        body.dark-mode .work-content h3 {
            color: #e0e0ff;
        }
        body.dark-mode .work-content p {
            color: #aaa;
        }
        body.dark-mode #activities {
            background: #0f0f1a !important;
        }
        body.dark-mode .activity-card {
            background: #1e1e3a;
        }
        body.dark-mode .activity-content h3 {
            color: #e0e0ff;
        }
        body.dark-mode .activity-content p {
            color: #aaa;
        }
        body.dark-mode .alumni-section {
            background: #0f0f1a;
        }
        body.dark-mode .alumni-card {
            background: linear-gradient(135deg, #1e1e3a 0%, #2a2a4a 100%);
        }
        body.dark-mode .member-card {
            background: linear-gradient(135deg, #1e1e3a 0%, #2a2a4a 100%);
        }
        body.dark-mode .member-name {
            color: #e0e0ff;
        }
        body.dark-mode .search-input {
            background: #1e1e3a;
            border-color: #333;
            color: #ddd;
        }
        body.dark-mode .filter-tab {
            background: #1e1e3a;
            color: #ddd;
        }
        body.dark-mode .filter-tab.active {
            background: #00d4ff;
            color: #1a1a2e;
        }

        nav {
            background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
            padding: 1rem 5%;
            position: fixed;
            width: 100%;
            top: 0;
            z-index: 1000;
            box-shadow: 0 2px 10px rgba(0,0,0,0.3);
        }

        .nav-container {
            max-width: 1200px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            color: #00d4ff;
            font-size: 1.5rem;
            font-weight: bold;
            text-decoration: none;
        }

        .nav-links {
            display: flex;
            list-style: none;
            gap: 1.5rem;
            flex-wrap: wrap;
        }

        .nav-links a {
            color: #fff;
            text-decoration: none;
            transition: color 0.3s;
            font-size: 0.95rem;
        }

        .nav-links a:hover {
            color: #00d4ff;
        }

        .nav-badge {
            background: #e74c3c;
            color: #fff;
            font-size: 0.65rem;
            padding: 1px 5px;
            border-radius: 8px;
            margin-left: 3px;
            vertical-align: super;
        }

        .theme-toggle {
            background: rgba(255,255,255,0.15);
            border: 1px solid rgba(255,255,255,0.3);
            color: #fff;
            font-size: 1.1rem;
            padding: 4px 10px;
            border-radius: 20px;
            cursor: pointer;
            transition: all 0.3s;
            margin-left: 0.5rem;
        }
        .theme-toggle:hover {
            background: rgba(255,255,255,0.3);
            transform: scale(1.1);
        }

        /* ======================================== */
        /* 语言切换器 */
        /* ======================================== */
        .lang-switcher {
            position: relative;
            margin-left: 0.3rem;
        }
        .lang-btn {
            background: rgba(255,255,255,0.15);
            border: 1px solid rgba(255,255,255,0.3);
            color: #fff;
            font-size: 0.85rem;
            padding: 4px 10px;
            border-radius: 20px;
            cursor: pointer;
            transition: all 0.3s;
            display: flex;
            align-items: center;
            gap: 4px;
        }
        .lang-btn:hover {
            background: rgba(255,255,255,0.3);
        }
        .lang-arrow {
            font-size: 0.6rem;
        }
        .lang-dropdown {
            display: none;
            position: absolute;
            top: 100%;
            right: 0;
            background: #1a1a2e;
            border: 1px solid rgba(255,255,255,0.2);
            border-radius: 8px;
            min-width: 130px;
            box-shadow: 0 8px 24px rgba(0,0,0,0.3);
            z-index: 2000;
            overflow: hidden;
        }
        .lang-dropdown.show {
            display: block;
            animation: langFadeIn 0.2s ease;
        }
        @keyframes langFadeIn {
            from { opacity: 0; transform: translateY(-5px); }
            to { opacity: 1; transform: translateY(0); }
        }
        .lang-option {
            padding: 8px 14px;
            color: #ccc;
            cursor: pointer;
            font-size: 0.85rem;
            transition: all 0.2s;
        }
        .lang-option:hover {
            background: rgba(0,212,255,0.15);
            color: #00d4ff;
        }
        .lang-option.active {
            background: rgba(0,212,255,0.1);
            color: #00d4ff;
        }

        .hero {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            padding: 120px 5% 80px;
            text-align: center;
            color: #fff;
            position: relative;
            overflow: hidden;
        }

        .hero-content-wrapper {
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 2rem;
            margin-bottom: 2rem;
        }

        .hero h1 {
            font-size: 3.5rem;
            margin-bottom: 1rem;
            animation: fadeInUp 1s ease;
        }

        .hero p {
            font-size: 1.2rem;
            margin-bottom: 2rem;
            opacity: 0.9;
        }

        .slider-container {
            position: relative;
            max-width: 1000px;
            margin: 0 auto 2rem auto;
            overflow: hidden;
            border-radius: 20px;
            background: rgba(255,255,255,0.15);
            backdrop-filter: blur(10px);
            box-shadow: 0 10px 40px rgba(0,0,0,0.2);
        }

        .slider-wrapper {
            display: flex;
            transition: none;
        }

        .slide-item {
            min-width: 100%;
            padding: 3rem 4rem;
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 1.5rem;
        }

        .slide-item h3 {
            font-size: 2rem;
            margin-bottom: 0.5rem;
        }

        .slide-item p {
            font-size: 1.2rem;
            opacity: 0.9;
            margin-bottom: 0;
        }

        .slide-icon {
            width: 80px;
            height: 80px;
            background: rgba(255,255,255,0.25);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 2rem;
        }

        .slider-btn {
            position: absolute;
            top: 50%;
            transform: translateY(-50%);
            background: rgba(255,255,255,0.3);
            border: none;
            color: #fff;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            cursor: pointer;
            font-size: 1.2rem;
            transition: all 0.3s;
            z-index: 10;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .slider-btn:hover {
            background: rgba(255,255,255,0.5);
        }

        .slider-btn.prev {
            left: 10px;
        }

        .slider-btn.next {
            right: 10px;
        }

        .slider-dots {
            display: flex;
            justify-content: center;
            gap: 0.5rem;
            margin-top: 1rem;
        }

        .slider-dot {
            width: 10px;
            height: 10px;
            border-radius: 50%;
            background: rgba(255,255,255,0.3);
            cursor: pointer;
            transition: all 0.3s;
        }

        .slider-dot.active {
            background: #fff;
            transform: scale(1.2);
        }

        .member-card {
            cursor: pointer;
            transition: transform 0.3s, box-shadow 0.3s;
        }

        .member-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 40px rgba(0,0,0,0.2);
        }

        .modal-overlay {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0,0,0,0.7);
            z-index: 2000;
            justify-content: center;
            align-items: center;
            opacity: 0;
            transition: opacity 0.3s;
        }

        .modal-overlay.active {
            display: flex;
            opacity: 1;
        }

        .member-modal {
            background: linear-gradient(145deg, #fff 0%, #f0f4ff 100%);
            width: 380px;
            max-height: 90vh;
            border-radius: 20px;
            padding: 30px;
            box-shadow: 0 20px 60px rgba(0,0,0,0.3);
            transform: scale(0.8);
            transition: transform 0.3s;
            overflow-y: auto;
            position: relative;
        }

        .modal-overlay.active .member-modal {
            transform: scale(1);
        }

        .modal-close {
            position: absolute;
            top: 15px;
            right: 15px;
            width: 35px;
            height: 35px;
            border: none;
            background: #f0f0f0;
            border-radius: 50%;
            font-size: 1.2rem;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: background 0.3s;
        }

        .modal-close:hover {
            background: #e0e0e0;
        }

        .modal-avatar-wrapper {
            display: flex;
            justify-content: center;
            margin-bottom: 20px;
        }

        .modal-avatar {
            width: 120px;
            height: 120px;
            border-radius: 50%;
            object-fit: cover;
            border: 4px solid #667eea;
            cursor: pointer;
            transition: transform 0.3s, box-shadow 0.3s;
        }

        .modal-avatar:hover {
            transform: scale(1.1);
            box-shadow: 0 10px 30px rgba(102,126,234,0.4);
        }

        .modal-name {
            text-align: center;
            font-size: 1.5rem;
            color: #1a1a2e;
            margin-bottom: 20px;
            font-weight: bold;
        }

        .modal-info-item {
            display: flex;
            padding: 12px 0;
            border-bottom: 1px solid #eee;
        }

        .modal-info-item:last-child {
            border-bottom: none;
        }

        .modal-info-label {
            width: 70px;
            font-weight: bold;
            color: #667eea;
            flex-shrink: 0;
        }

        .modal-info-value {
            color: #333;
            flex: 1;
            word-break: break-word;
        }

        .modal-skill {
            display: inline-block;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: #fff;
            padding: 4px 12px;
            border-radius: 15px;
            font-size: 0.85rem;
            margin: 2px;
        }

        .avatar-fullscreen {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0,0,0,0.95);
            z-index: 3000;
            justify-content: center;
            align-items: center;
            cursor: pointer;
        }

        .avatar-fullscreen.active {
            display: flex;
        }

        .avatar-fullscreen img {
            max-width: 90%;
            max-height: 90%;
            border-radius: 10px;
            box-shadow: 0 0 50px rgba(0,0,0,0.5);
        }

        .avatar-fullscreen-text {
            position: absolute;
            bottom: 30px;
            color: #fff;
            font-size: 1rem;
        }

        .btn {
            display: inline-block;
            padding: 12px 30px;
            background: #00d4ff;
            color: #1a1a2e;
            text-decoration: none;
            border-radius: 30px;
            font-weight: bold;
            transition: all 0.3s;
            border: none;
            cursor: pointer;
            font-size: 1rem;
        }

        .btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 5px 20px rgba(0,212,255,0.4);
        }

        .btn-outline {
            display: inline-block;
            padding: 12px 30px;
            background: transparent;
            color: #fff;
            border: 2px solid #fff;
            text-decoration: none;
            border-radius: 30px;
            font-weight: bold;
            transition: all 0.3s;
            cursor: pointer;
            font-size: 1rem;
        }

        .btn-outline:hover {
            background: rgba(255,255,255,0.15);
        }

        .section {
            padding: 60px 5%;
            max-width: 1200px;
            margin: 0 auto;
        }

        .section-title {
            text-align: center;
            font-size: 2.5rem;
            margin-bottom: 3rem;
            color: #1a1a2e;
        }

        .section-subtitle {
            text-align: center;
            font-size: 1rem;
            color: #999;
            margin-top: -2.5rem;
            margin-bottom: 2.5rem;
        }

        .about-content {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 3rem;
            align-items: center;
        }

        .about-text {
            font-size: 1.1rem;
            line-height: 1.8;
            color: #555;
        }

        .about-img-wrapper {
            text-align: center;
        }
        .about-img {
            width: 100%;
            border-radius: 15px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.1);
        }
        .about-img-caption {
            margin-top: 0.8rem;
            font-size: 0.9rem;
            color: #666;
            font-style: italic;
        }

        /* ======================================== */
        /* 公告栏 - 增强版 */
        /* ======================================== */
        .announcement-bar {
            background: linear-gradient(90deg, #fff3cd 0%, #ffe082 100%);
            border-bottom: 2px solid #ffc107;
            padding: 10px 5%;
            display: flex;
            align-items: center;
            gap: 0.8rem;
            flex-wrap: wrap;
            position: relative;
            overflow: hidden;
        }
        .announcement-label {
            background: #ffc107;
            color: #1a1a2e;
            padding: 3px 12px;
            border-radius: 4px;
            font-weight: bold;
            font-size: 0.85rem;
            white-space: nowrap;
        }
        .announcement-category {
            background: #e74c3c;
            color: #fff;
            padding: 2px 8px;
            border-radius: 10px;
            font-size: 0.75rem;
            white-space: nowrap;
        }
        .announcement-category.cat-notify { background: #3498db; }
        .announcement-category.cat-recruit { background: #e74c3c; }
        .announcement-category.cat-activity { background: #27ae60; }
        .announcement-category.cat-holiday { background: #8e44ad; }
        .announcement-text {
            color: #856404;
            font-size: 0.9rem;
            flex: 1;
            min-width: 200px;
            transition: opacity 0.4s;
        }
        .announcement-text.fade-out {
            opacity: 0;
        }
        .announcement-date {
            color: #aaa;
            font-size: 0.8rem;
            white-space: nowrap;
        }
        .announcement-dots {
            display: flex;
            gap: 5px;
            margin-left: auto;
        }
        .ann-dot {
            width: 8px;
            height: 8px;
            border-radius: 50%;
            background: rgba(255,193,7,0.4);
            cursor: pointer;
            transition: all 0.3s;
        }
        .ann-dot.active {
            background: #ffc107;
            transform: scale(1.3);
        }
        body.dark-mode .announcement-bar {
            background: linear-gradient(90deg, #2a2538 0%, #332b1a 100%);
            border-bottom-color: #ffc107;
        }
        body.dark-mode .announcement-text {
            color: #ffe082;
        }

        /* ======================================== */
        /* 招新专区 - 新增 */
        /* ======================================== */
        .recruit-section {
            background: linear-gradient(135deg, #f5f7fa 0%, #e8ecf3 100%);
        }
        .recruit-cards {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
            gap: 1.5rem;
        }
        .recruit-card {
            background: #fff;
            border-radius: 15px;
            padding: 2rem;
            text-align: center;
            box-shadow: 0 5px 20px rgba(0,0,0,0.08);
            transition: transform 0.3s;
            border-top: 4px solid #00d4ff;
        }
        .recruit-card:hover {
            transform: translateY(-5px);
        }
        .recruit-icon {
            font-size: 2.5rem;
            margin-bottom: 0.8rem;
        }
        .recruit-card h3 {
            color: #1a1a2e;
            margin-bottom: 0.5rem;
            font-size: 1.2rem;
        }
        .recruit-card p {
            color: #666;
            font-size: 0.9rem;
            line-height: 1.5;
        }
        .recruit-card .dept-tag {
            display: inline-block;
            background: #e8f4ff;
            color: #0080ff;
            padding: 3px 10px;
            border-radius: 12px;
            font-size: 0.8rem;
            margin-top: 0.8rem;
        }

        /* ======================================== */
        /* 作品展示 - 新增 */
        /* ======================================== */
        .works-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 1.5rem;
        }
        .work-card {
            background: #fff;
            border-radius: 15px;
            overflow: hidden;
            box-shadow: 0 5px 20px rgba(0,0,0,0.1);
            transition: transform 0.3s;
        }
        .work-card:hover {
            transform: translateY(-5px);
        }
        .work-img {
            width: 100%;
            height: 180px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 3rem;
            color: #fff;
        }
        .work-img.bg1 { background: linear-gradient(135deg, #667eea, #764ba2); }
        .work-img.bg2 { background: linear-gradient(135deg, #f093fb, #f5576c); }
        .work-img.bg3 { background: linear-gradient(135deg, #4facfe, #00f2fe); }
        .work-content {
            padding: 1.2rem;
        }
        .work-content h3 {
            color: #1a1a2e;
            margin-bottom: 0.3rem;
            font-size: 1.1rem;
        }
        .work-content p {
            color: #666;
            font-size: 0.9rem;
        }
        .work-author {
            color: #00d4ff;
            font-size: 0.85rem;
            margin-top: 0.5rem;
        }
        .work-placeholder {
            background: #f5f7fa;
            border: 2px dashed #ddd;
            border-radius: 15px;
            padding: 2rem;
            text-align: center;
            color: #999;
            min-height: 180px;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
        }
        .work-placeholder .icon {
            font-size: 2.5rem;
        }

        .activities-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 2rem;
        }

        .activity-card {
            background: #fff;
            border-radius: 15px;
            overflow: hidden;
            box-shadow: 0 5px 20px rgba(0,0,0,0.1);
            transition: transform 0.3s;
        }

        .activity-card:hover {
            transform: translateY(-10px);
        }

        .activity-img {
            width: 100%;
            height: 200px;
            object-fit: cover;
        }

        .activity-content {
            padding: 1.5rem;
        }

        .activity-content h3 {
            color: #1a1a2e;
            margin-bottom: 0.5rem;
        }

        .activity-content p {
            color: #666;
        }

        .filter-tabs {
            display: flex;
            justify-content: center;
            gap: 1rem;
            margin-bottom: 2rem;
            flex-wrap: wrap;
        }

        .filter-tab {
            padding: 8px 20px;
            background: #f5f7fa;
            border: none;
            border-radius: 20px;
            cursor: pointer;
            transition: all 0.3s;
            font-size: 0.9rem;
        }

        .filter-tab.active {
            background: #00d4ff;
            color: #1a1a2e;
        }

        .filter-tab:hover {
            background: #00d4ff;
            color: #1a1a2e;
        }

        .search-container {
            display: flex;
            justify-content: center;
            margin-bottom: 2rem;
        }

        .search-input {
            width: 100%;
            max-width: 400px;
            padding: 12px 20px;
            border: 2px solid #ddd;
            border-radius: 30px;
            font-size: 1rem;
            transition: border-color 0.3s;
        }

        .search-input:focus {
            outline: none;
            border-color: #00d4ff;
        }

        .members-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 2rem;
        }

        .member-card {
            text-align: center;
            padding: 2rem;
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            border-radius: 15px;
        }

        .member-avatar {
            width: 100px;
            height: 100px;
            border-radius: 50%;
            margin-bottom: 1rem;
            border: 3px solid #00d4ff;
        }

        .member-name {
            font-weight: bold;
            color: #1a1a2e;
        }

        .member-title {
            color: #666;
            font-size: 0.9rem;
        }

        /* ======================================== */
        /* 往届成员 - 新增 */
        /* ======================================== */
        .alumni-section {
            background: #f5f7fa;
        }
        .alumni-card {
            text-align: center;
            padding: 2rem;
            background: linear-gradient(135deg, #e8ecf3 0%, #d5dce8 100%);
            border-radius: 15px;
            cursor: pointer;
            transition: transform 0.3s, box-shadow 0.3s;
        }
        .alumni-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 30px rgba(0,0,0,0.15);
        }
        .alumni-badge {
            display: inline-block;
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: #fff;
            padding: 2px 10px;
            border-radius: 10px;
            font-size: 0.75rem;
            margin-bottom: 0.5rem;
        }
        .alumni-empty {
            text-align: center;
            color: #999;
            padding: 3rem;
            font-size: 1rem;
        }
        .jump-btn {
            display: inline-block;
            margin-top: 1.5rem;
            padding: 10px 25px;
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: #fff;
            border: none;
            border-radius: 25px;
            cursor: pointer;
            font-size: 0.9rem;
            transition: all 0.3s;
            text-decoration: none;
        }
        .jump-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(102,126,234,0.4);
        }

        .contact {
            background: #1a1a2e;
            color: #fff;
            padding: 60px 5%;
        }

        .contact-content {
            max-width: 1200px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 3rem;
        }

        .contact-info {
            line-height: 2;
        }

        .contact-form {
            display: flex;
            flex-direction: column;
            gap: 1rem;
        }

        .contact-form input,
        .contact-form textarea {
            padding: 12px;
            border: 2px solid #3a3a5c;
            border-radius: 8px;
            font-size: 1rem;
            background: rgba(255,255,255,0.1);
            color: #fff;
            transition: border-color 0.3s;
        }

        .contact-form input:focus,
        .contact-form textarea:focus {
            outline: none;
            border-color: #00d4ff;
        }

        .contact-form textarea {
            resize: none;
            height: 120px;
        }

        .contact-form input::placeholder,
        .contact-form textarea::placeholder {
            color: rgba(255,255,255,0.6);
        }

        .form-success {
            display: none;
            padding: 15px;
            background: rgba(0,255,136,0.2);
            border: 1px solid #00ff88;
            border-radius: 8px;
            color: #00ff88;
            text-align: center;
            margin-bottom: 1rem;
        }

        .form-error {
            display: none;
            padding: 15px;
            background: rgba(255,0,0,0.2);
            border: 1px solid #ff4444;
            border-radius: 8px;
            color: #ff4444;
            text-align: center;
            margin-bottom: 1rem;
        }

        .privacy-note {
            background: rgba(0,212,255,0.1);
            border: 1px solid rgba(0,212,255,0.3);
            border-radius: 10px;
            padding: 12px;
            margin-top: 1rem;
            font-size: 0.85rem;
            color: #00d4ff;
            line-height: 1.5;
        }

        footer {
            background: #0f0f1a;
            color: #888;
            text-align: center;
            padding: 2rem;
        }

        footer a {
            color: #00d4ff;
            text-decoration: none;
        }

        .float-trigger {
            position: fixed;
            bottom: 80px;
            right: 30px;
            width: 60px;
            height: 60px;
            background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            box-shadow: 0 4px 20px rgba(0,0,0,0.4);
            z-index: 500;
            transition: all 0.3s;
            border: 2px solid #00d4ff;
        }

        .float-trigger:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 30px rgba(0,212,255,0.3);
        }

        .float-trigger-icon {
            font-size: 24px;
        }

        .float-trigger-text {
            position: absolute;
            right: 70px;
            top: 50%;
            transform: translateY(-50%);
            background: rgba(26,26,46,0.95);
            color: #00d4ff;
            padding: 8px 15px;
            border-radius: 20px;
            font-size: 14px;
            white-space: nowrap;
            opacity: 0;
            visibility: hidden;
            transition: all 0.3s;
            border: 1px solid rgba(0,212,255,0.3);
        }

        .float-trigger:hover .float-trigger-text {
            opacity: 1;
            visibility: visible;
        }

        .qq-qrcode-modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0,0,0,0.7);
            z-index: 2000;
            justify-content: center;
            align-items: center;
            opacity: 0;
            transition: opacity 0.3s;
        }

        .qq-qrcode-modal.active {
            display: flex;
            opacity: 1;
        }

        .qrcode-content {
            background: linear-gradient(145deg, #1a1a2e 0%, #16213e 100%);
            border-radius: 20px;
            padding: 30px;
            box-shadow: 0 20px 60px rgba(0,0,0,0.5);
            transform: scale(0.8);
            transition: transform 0.3s;
            position: relative;
            border: 2px solid #00d4ff;
        }

        .qq-qrcode-modal.active .qrcode-content {
            transform: scale(1);
        }

        /* ======================================== */
        /* 返回顶部按钮 - 新增 */
        /* ======================================== */
        .back-to-top {
            position: fixed;
            bottom: 30px;
            right: 30px;
            width: 45px;
            height: 45px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            box-shadow: 0 4px 15px rgba(102,126,234,0.4);
            z-index: 999;
            opacity: 0;
            visibility: hidden;
            transition: all 0.3s;
            border: none;
            color: #fff;
            font-size: 1.2rem;
        }
        .back-to-top.visible {
            opacity: 1;
            visibility: visible;
        }
        .back-to-top:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 20px rgba(102,126,234,0.5);
        }

        .qrcode-close {
            position: absolute;
            top: -40px;
            right: 0;
            width: 35px;
            height: 35px;
            background: rgba(26,26,46,0.9);
            border: 2px solid #00d4ff;
            border-radius: 50%;
            color: #00d4ff;
            font-size: 18px;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.3s;
        }

        .qrcode-close:hover {
            background: #00d4ff;
            color: #1a1a2e;
        }

        .qrcode-image {
            width: 250px;
            height: 250px;
            border-radius: 15px;
            display: block;
            margin-bottom: 15px;
            background: #fff;
            padding: 10px;
            border: 3px solid #00d4ff;
            box-shadow: 0 0 20px rgba(0,212,255,0.2);
        }

        .qrcode-title {
            text-align: center;
            color: #fff;
            font-size: 18px;
            font-weight: bold;
            margin-bottom: 5px;
        }

        .qrcode-desc {
            text-align: center;
            color: #888;
            font-size: 14px;
        }

        /* ======================================== */
        /* 往届成员弹窗样式 - 新增 */
        /* ======================================== */
        .alumni-modal-overlay {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0,0,0,0.7);
            z-index: 2000;
            justify-content: center;
            align-items: center;
            opacity: 0;
            transition: opacity 0.3s;
        }
        .alumni-modal-overlay.active {
            display: flex;
            opacity: 1;
        }
        .alumni-modal {
            background: linear-gradient(145deg, #fff 0%, #f0f4ff 100%);
            width: 420px;
            max-height: 85vh;
            border-radius: 20px;
            padding: 30px;
            box-shadow: 0 20px 60px rgba(0,0,0,0.3);
            transform: scale(0.8);
            transition: transform 0.3s;
            overflow-y: auto;
            position: relative;
        }
        .alumni-modal-overlay.active .alumni-modal {
            transform: scale(1);
        }

        @keyframes fadeInUp {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        @media (max-width: 768px) {
            .nav-links {
                gap: 0.8rem;
            }
            
            .hero h1 {
                font-size: 2.5rem;
            }
            
            .about-content {
                grid-template-columns: 1fr;
            }
            
            .contact-content {
                grid-template-columns: 1fr;
            }
        }

        /* ======================================== */
        /* 汉堡菜单按钮 - 默认隐藏，移动端显示 */
        /* ======================================== */
        .hamburger {
            display: none;
            flex-direction: column;
            justify-content: space-around;
            width: 30px;
            height: 30px;
            background: transparent;
            border: none;
            cursor: pointer;
            padding: 0;
            z-index: 1001;
        }
        .hamburger span {
            display: block;
            width: 100%;
            height: 3px;
            background: #00d4ff;
            border-radius: 3px;
            transition: all 0.3s ease;
        }
        .hamburger.active span:nth-child(1) {
            transform: rotate(45deg) translate(6px, 6px);
        }
        .hamburger.active span:nth-child(2) {
            opacity: 0;
        }
        .hamburger.active span:nth-child(3) {
            transform: rotate(-45deg) translate(6px, -6px);
        }

        /* ======================================== */
        /* 移动端响应式导航 */
        /* ======================================== */
        @media (max-width: 768px) {
            .hamburger {
                display: flex;
            }
            .nav-links {
                position: fixed;
                top: 0;
                right: -100%;
                width: 250px;
                height: 100vh;
                background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
                flex-direction: column;
                padding: 80px 20px 20px;
                gap: 1rem;
                transition: right 0.3s ease;
                box-shadow: -5px 0 15px rgba(0,0,0,0.3);
                z-index: 999;
            }
            .nav-links.mobile-open {
                right: 0;
            }
            .nav-links li {
                width: 100%;
            }
            .nav-links a {
                display: block;
                padding: 10px 0;
                font-size: 1.1rem;
                border-bottom: 1px solid rgba(255,255,255,0.1);
            }
            .lang-switcher {
                margin-top: 1rem;
            }
        }

        /* ======================================== */
        /* 报名按钮样式 */
        /* ======================================== */
        .recruit-btn {
            display: inline-block;
            margin-top: 12px;
            padding: 8px 24px;
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: #fff;
            border: none;
            border-radius: 20px;
            font-size: 0.9rem;
            cursor: pointer;
            transition: all 0.3s;
        }
        .recruit-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 12px rgba(102,126,234,0.4);
        }
        body.dark-mode .recruit-btn {
            background: linear-gradient(135deg, #00d4ff, #0099cc);
            color: #1a1a2e;
        }

        /* ======================================== */
        /* 报名弹窗样式 */
        /* ======================================== */
        .reg-modal {
            background: #fff;
            border-radius: 16px;
            padding: 30px;
            max-width: 500px;
            width: 90%;
            max-height: 90vh;
            overflow-y: auto;
            position: relative;
            box-shadow: 0 20px 60px rgba(0,0,0,0.3);
        }
        body.dark-mode .reg-modal {
            background: #1a1a2e;
            color: #ddd;
        }
        .reg-modal-title {
            font-size: 1.4rem;
            margin-bottom: 16px;
            color: #333;
        }
        body.dark-mode .reg-modal-title {
            color: #e0e0ff;
        }
        .reg-dept-display {
            display: none;
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: #fff;
            padding: 8px 16px;
            border-radius: 8px;
            font-weight: bold;
            margin-bottom: 16px;
            text-align: center;
        }
        .reg-form input,
        .reg-form textarea {
            width: 100%;
            padding: 10px 14px;
            margin-bottom: 10px;
            border: 1px solid #ddd;
            border-radius: 8px;
            font-size: 0.95rem;
            font-family: inherit;
        }
        body.dark-mode .reg-form input,
        body.dark-mode .reg-form textarea {
            background: #0f0f1a;
            border-color: #333;
            color: #ddd;
        }
        .reg-form-row {
            display: flex;
            gap: 10px;
        }
        .reg-form-row input {
            flex: 1;
        }
        .reg-qq-note {
            font-size: 0.85rem;
            color: #888;
            margin: 8px 0;
            padding: 8px;
            background: #f5f5f5;
            border-radius: 8px;
        }
        body.dark-mode .reg-qq-note {
            background: #0f0f1a;
            color: #888;
        }
        .reg-submit-btn {
            width: 100%;
            margin-top: 8px;
        }
        .reg-result {
            display: none;
            margin-top: 10px;
            padding: 10px;
            border-radius: 8px;
            font-size: 0.9rem;
        }
        .reg-result.reg-success {
            background: #d4edda;
            color: #155724;
        }
        .reg-result.reg-error {
            background: #f8d7da;
            color: #721c24;
        }
        body.dark-mode .reg-result.reg-success {
            background: #1a3a1a;
            color: #90ee90;
        }
        body.dark-mode .reg-result.reg-error {
            background: #3a1a1a;
            color: #ffb0b0;
        }

/* ======================================== */
/* 站内搜索 */
/* ======================================== */
.site-search-btn {
    background: rgba(255,255,255,0.15);
    border: 1px solid rgba(255,255,255,0.3);
    color: #fff;
    font-size: 1rem;
    padding: 4px 10px;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s;
    margin-left: 0.5rem;
}
.site-search-btn:hover {
    background: rgba(255,255,255,0.3);
    transform: scale(1.1);
}

.site-search-overlay {
    display: none;
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    background: rgba(0,0,0,0.7);
    z-index: 2000;
    justify-content: center;
    align-items: flex-start;
    padding-top: 80px;
    animation: fadeIn 0.2s;
}
.site-search-overlay.active { display: flex; }

.site-search-box {
    background: #fff;
    width: 90%;
    max-width: 600px;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 8px 32px rgba(0,0,0,0.3);
    max-height: 70vh;
    display: flex;
    flex-direction: column;
}
body.dark-mode .site-search-box { background: #1a1a2e; }

.search-input-wrapper {
    display: flex;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid #eee;
}
body.dark-mode .search-input-wrapper { border-bottom-color: #333; }

#siteSearchInput {
    flex: 1;
    border: none;
    outline: none;
    font-size: 1.1rem;
    background: transparent;
    color: #333;
}
body.dark-mode #siteSearchInput { color: #ddd; }

.search-close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: #999;
    cursor: pointer;
    padding: 0 8px;
    line-height: 1;
}
.search-close-btn:hover { color: #ff6b6b; }

.search-results {
    overflow-y: auto;
    padding: 8px 0;
}
.search-hint {
    text-align: center;
    padding: 30px;
    color: #999;
    font-size: 0.9rem;
}
.search-result-item {
    display: flex;
    align-items: center;
    padding: 12px 20px;
    cursor: pointer;
    transition: background 0.2s;
    border-bottom: 1px solid #f5f5f5;
    gap: 12px;
}
body.dark-mode .search-result-item { border-bottom-color: #222; }
.search-result-item:hover { background: #f0f7ff; }
body.dark-mode .search-result-item:hover { background: #16213e; }

.search-result-icon { font-size: 1.5rem; flex-shrink: 0; }
.search-result-info { flex: 1; min-width: 0; }
.search-result-title {
    font-size: 0.95rem;
    color: #333;
    font-weight: 500;
    margin-bottom: 2px;
}
body.dark-mode .search-result-title { color: #e0e0ff; }
.search-result-desc {
    font-size: 0.8rem;
    color: #888;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.search-result-tag {
    font-size: 0.7rem;
    padding: 2px 8px;
    border-radius: 10px;
    background: #e8f4ff;
    color: #00a0e9;
    white-space: nowrap;
}
body.dark-mode .search-result-tag { background: #1a3a5a; color: #00d4ff; }
.search-no-result {
    text-align: center;
    padding: 30px;
    color: #999;
}

@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

/* Mobile responsive */
@media (max-width: 768px) {
    .site-search-btn { margin-left: 0; }
    .site-search-box { width: 95%; max-height: 60vh; }
    #siteSearchInput { font-size: 1rem; }
}