.hero {
    background: linear-gradient(rgba(44, 62, 80, 0.85), rgba(44, 62, 80, 0.85)), url('../images/activities.jpg');
    background-size: cover;
    background-position: center;
    min-height: 70vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: white;
    position: relative;
    margin-top: 100px;
}

.hero-content {
    z-index: 2;
    max-width: 800px;
    padding: 0 20px;
}

.hero-title {
    font-family: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', serif;
    font-size: 52px;
    font-weight: 700;
    margin-bottom: 20px;
    letter-spacing: 2px;
    line-height: 1.3;
}

.hero-subtitle {
    font-size: 19px;
    opacity: 0.9;
    margin-bottom: 35px;
    line-height: 1.6;
}

.hero-cta {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 14px 32px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    font-size: 16px;
}

.btn-primary {
    background: var(--accent);
    color: white;
}

.btn-primary:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(52, 152, 219, 0.4);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: white;
    color: var(--primary);
}

.quick-links-section {
    padding: 60px 0;
    background: white;
}

.section-header {
    text-align: center;
    margin-bottom: 45px;
}

.section-header h2 {
    font-family: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', serif;
    font-size: 32px;
    color: var(--primary);
    margin-bottom: 10px;
}

.section-header p {
    color: var(--gray);
    font-size: 16px;
}

.divider {
    width: 60px;
    height: 3px;
    background: var(--accent);
    margin: 15px auto;
    border-radius: 2px;
}

.quick-links-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 25px;
}

.quick-link-card {
    background: white;
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

.quick-link-blue {
    border-top: 4px solid #1a5490;
    background: linear-gradient(135deg, #f0f7ff 0%, #ffffff 100%);
}

.quick-link-blue h3 {
    color: #1a5490;
}

.quick-link-teal {
    border-top: 4px solid #11998e;
    background: linear-gradient(135deg, #f0fff5 0%, #ffffff 100%);
}

.quick-link-teal h3 {
    color: #11998e;
}

.quick-link-purple {
    border-top: 4px solid #667eea;
    background: linear-gradient(135deg, #f5f3ff 0%, #ffffff 100%);
}

.quick-link-purple h3 {
    color: #667eea;
}

.quick-link-orange {
    border-top: 4px solid #f39c12;
    background: linear-gradient(135deg, #fff8f0 0%, #ffffff 100%);
}

.quick-link-orange h3 {
    color: #f39c12;
}

.quick-link-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.12);
}

.quick-link-icon {
    font-size: 40px;
    margin-bottom: 15px;
}

.quick-link-card h3 {
    font-size: 18px;
    color: var(--primary);
    margin-bottom: 8px;
    font-weight: 600;
}

.quick-link-card p {
    font-size: 14px;
    color: var(--gray);
    margin: 0;
}

.about-section {
    padding: 70px 0;
    background: var(--light);
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
}

.lead {
    font-size: 18px;
    color: var(--dark);
    text-align: center;
    margin-bottom: 45px;
    line-height: 1.8;
}

.beliefs h3 {
    font-size: 22px;
    color: var(--primary);
    margin-bottom: 25px;
    text-align: center;
}

.belief-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.belief-card {
    background: linear-gradient(135deg, #ffffff 0%, #f8fafc 100%);
    padding: 35px 30px;
    border-radius: 16px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
    text-align: center;
    position: relative;
    overflow: hidden;
    transition: all 0.4s ease;
    border: 1px solid rgba(26, 84, 144, 0.08);
}

.belief-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, #1a5490, #2c7cc1);
    border-radius: 0 0 10px 10px;
}

.belief-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 35px rgba(26, 84, 144, 0.15);
    background: linear-gradient(135deg, #f0f7ff 0%, #ffffff 100%);
}

.belief-icon {
    font-size: 42px;
    margin-bottom: 20px;
    display: inline-block;
    width: 80px;
    height: 80px;
    line-height: 80px;
    background: linear-gradient(135deg, rgba(26, 84, 144, 0.1), rgba(44, 124, 193, 0.1));
    border-radius: 50%;
    transition: transform 0.3s ease;
}

.belief-card:hover .belief-icon {
    transform: scale(1.1);
}

.belief-card p {
    font-size: 15px;
    color: #4a5568;
    line-height: 1.8;
    margin: 0;
    font-weight: 400;
}

.locations {
    display: flex;
    justify-content: center;
    gap: 80px;
    margin-top: 50px;
    padding-top: 40px;
    border-top: 1px solid #eee;
}

.location-card {
    text-align: center;
}

.location-card h4 {
    font-size: 16px;
    color: var(--primary);
    margin-bottom: 5px;
    font-weight: 600;
}

.location-subtitle {
    font-size: 12px;
    color: var(--gray);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 8px;
}

.location-card p {
    font-size: 14px;
    color: var(--dark);
    margin: 0;
}

.team-section {
    padding: 70px 0;
    background: white;
}

.section-subtitle {
    font-family: Georgia, 'Times New Roman', Times, serif;
    font-size: 16px;
    color: var(--gray);
    text-transform: uppercase;
    letter-spacing: 2px;
}

.subsection-title {
    font-size: 20px;
    color: var(--primary);
    margin-bottom: 30px;
    text-align: center;
}

.team-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.team-card {
    background: white;
    padding: 25px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
}

.team-photo {
    position: relative;
    width: 120px;
    height: 120px;
    margin: 0 auto 15px;
    border-radius: 50%;
    overflow: hidden;
}

.team-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: none;
    position: relative;
    z-index: 2;
}

.team-card .team-photo .placeholder-photo {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent), #2980b9);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 24px;
    font-weight: 700;
    margin: 0;
    z-index: 1;
}

.team-card h4 {
    font-size: 18px;
    color: var(--primary);
    margin-bottom: 8px;
}

.team-role {
    font-size: 13px;
    color: var(--accent);
    font-weight: 500;
    margin-bottom: 15px;
}

.team-bio p {
    font-size: 13px;
    color: #666;
    line-height: 1.6;
    margin-bottom: 8px;
}

.team-bio p:last-child {
    margin-bottom: 0;
}

.mentor-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 25px;
    margin-top: 40px;
}

.mentor-card {
    background: var(--light);
    padding: 22px;
    border-radius: var(--radius);
    border-left: 4px solid var(--accent);
}

.mentor-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.mentor-header h4 {
    font-size: 16px;
    color: var(--primary);
    margin: 0;
}

.mentor-school {
    font-size: 12px;
    background: var(--accent);
    color: white;
    padding: 4px 10px;
    border-radius: 15px;
    font-weight: 500;
}

.mentor-card p {
    font-size: 13px;
    color: #555;
    line-height: 1.6;
    margin-bottom: 8px;
}

.mentor-specialty {
    font-size: 12px !important;
    color: var(--gray) !important;
    font-style: italic;
}

.services-section {
    padding: 70px 0;
    background: var(--light);
}

.service-model h3 {
    font-size: 22px;
    color: var(--primary);
    text-align: center;
    margin-bottom: 10px;
}

.model-description {
    text-align: center;
    color: var(--gray);
    font-size: 15px;
    margin-bottom: 40px;
}

.service-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 22px;
    margin-bottom: 40px;
}

.service-card {
    background: white;
    padding: 25px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
    position: relative;
}

.service-number {
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 30px;
    height: 30px;
    background: var(--accent);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 600;
}

.service-card h4 {
    font-size: 16px;
    color: var(--primary);
    margin-bottom: 10px;
    margin-top: 15px;
}

.service-card p {
    font-size: 13px;
    color: #555;
    line-height: 1.6;
    margin: 0;
}

.service-highlights {
    display: flex;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
}

.highlight-item {
    display: flex;
    align-items: center;
    gap: 8px;
}

.highlight-icon {
    font-size: 18px;
}

.highlight-item p {
    font-size: 14px;
    color: var(--dark);
    margin: 0;
}

.service-process h3 {
    font-size: 22px;
    color: var(--primary);
    text-align: center;
    margin: 50px 0 35px;
}

.process-timeline {
    max-width: 900px;
    margin: 0 auto;
}

.timeline-item {
    display: flex;
    gap: 20px;
    padding: 20px 0;
    border-bottom: 1px dashed #ddd;
}

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

.timeline-icon {
    width: 40px;
    height: 40px;
    background: var(--accent);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    flex-shrink: 0;
}

.timeline-content h4 {
    font-size: 16px;
    color: var(--primary);
    margin-bottom: 5px;
}

.timeline-content p {
    font-size: 14px;
    color: #555;
    margin: 0;
}

.service-packages h3 {
    font-size: 22px;
    color: var(--primary);
    text-align: center;
    margin: 50px 0 30px;
}

.packages-table {
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.package-header {
    display: flex;
    background: var(--primary);
    color: white;
    padding: 18px 25px;
    font-weight: 600;
}

.package-category {
    width: 28%;
}

.package-details {
    width: 72%;
}

.package-row {
    display: flex;
    padding: 18px 25px;
    border-bottom: 1px solid #eee;
}

.package-row:last-child {
    border-bottom: none;
}

.package-row .package-category {
    font-weight: 600;
    color: var(--primary);
}

.package-row ul {
    margin: 0;
    padding-left: 20px;
    columns: 2;
}

.package-row li {
    font-size: 14px;
    color: #555;
    margin-bottom: 6px;
}

.value-added {
    margin-top: 30px;
    padding: 20px;
    background: var(--accent-light);
    border-radius: var(--radius);
}

.value-added h4 {
    font-size: 16px;
    color: var(--primary);
    margin-bottom: 12px;
}

.value-added ul {
    margin: 0;
    padding-left: 20px;
}

.value-added li {
    font-size: 14px;
    color: #555;
    margin-bottom: 8px;
}

.features-section {
    padding: 70px 0;
    background: white;
}

.feature-content {
    max-width: 1100px;
    margin: 0 auto;
}

.summer-programs h3 {
    font-size: 22px;
    color: var(--primary);
    margin-bottom: 25px;
}

.summer-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-bottom: 30px;
}

.summer-card {
    background: var(--light);
    padding: 25px;
    border-radius: var(--radius);
    text-align: center;
    border: 2px solid transparent;
    transition: var(--transition);
}

.summer-card:hover {
    border-color: var(--accent);
}

.summer-logo {
    font-size: 32px;
    font-weight: 700;
    color: var(--accent);
    margin-bottom: 10px;
}

.summer-card h4 {
    font-size: 14px;
    color: var(--primary);
    margin: 0;
}

.feature-highlights {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 10px;
}

.check-icon {
    color: var(--accent);
    font-weight: bold;
    font-size: 18px;
}

.feature-item p {
    font-size: 14px;
    color: #555;
    margin: 0;
}

.research-programs {
    margin-top: 60px;
    padding-top: 40px;
    border-top: 1px solid #eee;
}

.research-programs h3 {
    font-size: 22px;
    color: var(--primary);
    margin-bottom: 12px;
}

.research-intro {
    font-size: 15px;
    color: #555;
    line-height: 1.7;
    margin-bottom: 30px;
}

.research-importance h4 {
    font-size: 18px;
    color: var(--primary);
    margin-bottom: 20px;
}

.importance-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.importance-card {
    background: white;
    padding: 22px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    position: relative;
    padding-left: 55px;
}

.importance-number {
    position: absolute;
    left: 15px;
    top: 50%;
    transform: translateY(-50%);
    width: 32px;
    height: 32px;
    background: var(--accent);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 600;
}

.importance-card p {
    font-size: 14px;
    color: #555;
    line-height: 1.6;
    margin: 0;
}

.research-advantage {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 25px;
    margin-top: 35px;
}

.advantage-box {
    background: var(--light);
    padding: 25px;
    border-radius: var(--radius);
}

.advantage-box h4 {
    font-size: 18px;
    color: var(--primary);
    margin-bottom: 12px;
}

.advantage-box p {
    font-size: 14px;
    color: #555;
    line-height: 1.6;
    margin-bottom: 15px;
}

.project-details h5 {
    font-size: 15px;
    color: var(--accent);
    margin-bottom: 10px;
}

.project-details ul {
    margin: 0;
    padding-left: 20px;
}

.project-details li {
    font-size: 13px;
    color: #555;
    margin-bottom: 6px;
}

.formula-box {
    background: linear-gradient(135deg, var(--accent), #2980b9);
    padding: 25px;
    border-radius: var(--radius);
    
    /* 整体盒子：水平+垂直居中 */
    display: flex;
    flex-direction: column;  /* 关键：纵向排成三行，不是三列 */
    justify-content: center; /* 垂直居中 */
    align-items: center;     /* 每行文字水平居中 */
    
    min-height: 120px;       /* 给高度才看得见垂直居中，可改 */
    line-height: 1.8;        /* 三行之间行距 */
}

.formula {
    font-size: 15px;
    color: white;
    font-weight: 500;
    text-align: center;
    margin: 0;
}

.formula-line1, .formula-line2, .formula-line3 {
    margin: 0;
    font-weight: bold;
    color: white;
}

.formula-line1 {
    font-size: 1.6rem;
    margin-bottom: 8px;
}

.formula-line2 {
    font-size: 2.5rem;
    margin-bottom: 8px;
}

.formula-line3 {
    font-size: 1.4rem;
}

.contact-section {
    padding: 70px 0;
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
}

.contact-section .section-header h2 {
    color: white;
}

.contact-section .section-header p {
    color: rgba(255, 255, 255, 0.7);
}

.contact-section .divider {
    background: white;
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 40px;
    margin-top: 30px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.contact-card {
    background: rgba(255, 255, 255, 0.1);
    padding: 22px;
    border-radius: var(--radius);
}

.contact-card h4 {
    font-size: 16px;
    color: white;
    margin-bottom: 8px;
}

.contact-card p {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.8);
    margin: 0;
}

.contact-form {
    background: white;
    padding: 30px;
    border-radius: var(--radius);
}

.contact-form h3 {
    font-size: 20px;
    color: var(--primary);
    margin-bottom: 25px;
}

.form-group {
    margin-bottom: 18px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 14px;
    font-family: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    transition: var(--transition);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

.contact-form .btn-primary {
    width: 100%;
    border: none;
    cursor: pointer;
}

.footer {
    background: var(--dark);
    padding: 50px 0 20px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    margin-bottom: 35px;
}

.footer-brand h3 {
    font-size: 22px;
    color: white;
    margin-bottom: 8px;
    font-weight: 600;
}

.footer-brand p {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
    margin: 0;
}

.footer-links {
    display: flex;
    gap: 60px;
}

.footer-column h4 {
    font-size: 14px;
    color: white;
    margin-bottom: 15px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.footer-column ul {
    margin: 0;
    padding: 0;
    list-style: none;
}

.footer-column li {
    margin-bottom: 10px;
}

.footer-column a {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
    text-decoration: none;
    transition: var(--transition);
}

.footer-column a:hover {
    color: white;
}

.footer-bottom {
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
}

.footer-bottom p {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.5);
    margin: 0;
}

@media (max-width: 992px) {
    .quick-links-grid,
    .belief-grid,
    .team-grid,
    .mentor-grid,
    .service-grid,
    .importance-grid {
        grid-template-columns: 1fr;
    }

    .research-advantage {
        grid-template-columns: 1fr;
    }

    .contact-content {
        grid-template-columns: 1fr;
    }

    .locations {
        flex-direction: column;
        gap: 20px;
    }
}

@media (max-width: 768px) {
    .hero {
        margin-top: 0;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 16px;
    }

    .footer-content {
        flex-direction: column;
        gap: 30px;
    }

    .footer-links {
        flex-direction: row;
        flex-wrap: wrap;
        gap: 15px;
        justify-content: center;
    }

    .footer-column {
        flex: none;
    }

    .footer-column h4 {
        display: none;
    }

    .footer-column ul {
        display: contents;
    }

    .footer-column li {
        display: inline-block;
        margin-bottom: 0;
        margin-right: 15px;
    }

    .footer-column li:last-child {
        margin-right: 0;
    }

    .package-row ul {
        columns: 1;
    }
}

/* Side Navigation Styles */
.side-nav {
    position: fixed;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    z-index: 9999;
    font-family: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
}

.side-nav-toggle {
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 36px;
    height: 36px;
    background: var(--accent);
    color: white;
    border-radius: 8px 0 0 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    box-shadow: -3px 0 10px rgba(0, 0, 0, 0.1);
}

.side-nav-toggle:hover {
    background: #2980b9;
}

.side-nav-icon {
    font-size: 18px;
}

.side-nav-menu {
    display: flex;
    flex-direction: column;
    gap: 0;
    background: white;
    border-radius: 12px 0 0 12px;
    box-shadow: -3px 0 20px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    max-height: 0;
    transition: max-height 0.4s ease, opacity 0.3s ease;
    opacity: 0;
}

.side-nav.active .side-nav-menu {
    max-height: 500px;
    opacity: 1;
}

.side-nav.active .side-nav-toggle {
    border-radius: 12px 0 0 12px;
}

.side-nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 20px;
    text-decoration: none;
    color: var(--primary);
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
    border-bottom: 1px solid #f0f0f0;
}

.side-nav-item:last-child {
    border-bottom: none;
}

.side-nav-item:hover {
    background: var(--accent-light);
    color: var(--accent);
}

.side-nav-item.active {
    background: var(--accent);
    color: white;
}

.side-nav-item.active .side-nav-dot {
    background: white;
}

.side-nav-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--accent);
    transition: all 0.3s ease;
    flex-shrink: 0;
}

.side-nav-text {
    white-space: nowrap;
}

/* Hide side nav on mobile */
@media (max-width: 992px) {
    .side-nav {
        display: none;
    }
}