/* ==================== 全局样式 ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 主色：护眼青蓝，沉稳大气 */
    --primary: #2563EB;
    --primary-dark: #1D4ED8;
    --primary-light: #60A5FA;
    /* 次色：教师端温和橙，降低饱和度更舒适 */
    --secondary: #EA8B2F;
    --secondary-dark: #D06B15;
    /* 强调色：家长端自然绿，天然护眼 */
    --accent: #059669;
    --accent-dark: #047857;
    /* 背景/文字：暖白底色，减少蓝光刺激 */
    --slate-50: #F8FAF7;
    --slate-100: #F0F4F0;
    --slate-200: #E1E8E1;
    --slate-300: #C5D0C5;
    --slate-400: #8FA89F;
    --slate-500: #5F7870;
    --slate-600: #3D5950;
    --slate-700: #2A3F38;
    --slate-800: #1A2E28;
    --slate-900: #0D1F1A;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB',
        'Microsoft YaHei', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    color: var(--slate-800);
    background-color: var(--slate-50);
    line-height: 1.6;
}

html {
    scroll-behavior: smooth;
}

a {
    text-decoration: none;
    color: inherit;
}

button {
    cursor: pointer;
    border: none;
    outline: none;
    font-family: inherit;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }
}

/* ==================== 按钮样式 ==================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 32px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
    text-align: center;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    box-shadow: 0 4px 6px -1px rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--primary-dark), #1D4ED8);
    box-shadow: 0 10px 15px -3px rgba(59, 130, 246, 0.4);
    transform: translateY(-2px);
}

.btn-outline {
    background: white;
    color: var(--primary);
    border: 2px solid var(--primary);
}

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

.btn-full {
    width: 100%;
}

.btn-small {
    padding: 8px 24px;
    font-size: 14px;
}

.btn-large {
    padding: 16px 48px;
    font-size: 18px;
}

/* ==================== 导航栏 ==================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    z-index: 1000;
}

.navbar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 20px;
    font-weight: bold;
}

.logo-text {
    font-size: 20px;
    font-weight: bold;
    color: var(--slate-900);
}

.nav-links {
    display: flex;
    gap: 32px;
    list-style: none;
}

.nav-links a {
    color: var(--slate-600);
    font-weight: 500;
    transition: color 0.3s;
    position: relative;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary);
}

.nav-links a.active::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary);
}

/* ==================== 导航栏角色切换组 ==================== */
.nav-role-group {
    display: flex;
    gap: 8px;
    align-items: center;
}

.nav-role-btn {
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.nav-role-student {
    background: #eff6ff;
    color: #2563eb;
    border: 1.5px solid #bfdbfe;
}
.nav-role-student:hover, .nav-role-student.active {
    background: #2563eb;
    color: white;
}

.nav-role-parent {
    background: #f0fdf4;
    color: #16a34a;
    border: 1.5px solid #bbf7d0;
}
.nav-role-parent:hover, .nav-role-parent.active {
    background: #16a34a;
    color: white;
}

.nav-role-teacher {
    background: #fff7ed;
    color: #ea580c;
    border: 1.5px solid #fed7aa;
}
.nav-role-teacher:hover, .nav-role-teacher.active {
    background: #ea580c;
    color: white;
}

/* ==================== 汉堡菜单按钮 ==================== */
.hamburger {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 24px;
    height: 18px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: 1001;
}

.hamburger span {
    display: block;
    width: 100%;
    height: 2px;
    background: var(--slate-700);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.hamburger.open span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}
.hamburger.open span:nth-child(2) {
    opacity: 0;
}
.hamburger.open span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

/* ==================== 移动端导航 ==================== */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-links {
        display: none;
        position: fixed;
        top: 64px;
        left: 0;
        right: 0;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(12px);
        flex-direction: column;
        gap: 0;
        padding: 8px 0 16px;
        box-shadow: 0 8px 24px rgba(0,0,0,0.12);
        z-index: 999;
    }

    .nav-links.open {
        display: flex;
    }

    .nav-links li {
        border-bottom: 1px solid var(--slate-100);
    }

    .nav-links li:last-child {
        border-bottom: none;
    }

    .nav-links a {
        display: block;
        padding: 14px 24px;
        font-size: 15px;
    }

    .nav-links a.active::after {
        display: none;
    }

    .nav-links a.active {
        background: #eff6ff;
        border-left: 3px solid var(--primary);
        padding-left: 21px;
    }

    .nav-role-group {
        display: none;
    }
}

/* ==================== 页面头部 ==================== */
.page-header {
    padding: 160px 0 80px;
    background: linear-gradient(135deg, #EFF6FF 0%, #FFFFFF 50%, #FFF7ED 100%);
    position: relative;
    overflow: hidden;
}

.page-header::before {
    content: '';
    position: absolute;
    top: 80px;
    right: 0;
    width: 384px;
    height: 384px;
    background: #BFDBFE;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.3;
}

.page-header::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 384px;
    height: 384px;
    background: #FDBA74;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.3;
}

.page-header-content {
    text-align: center;
    position: relative;
    z-index: 1;
}

.page-title {
    font-size: clamp(36px, 6vw, 56px);
    font-weight: 800;
    color: var(--slate-900);
    margin-bottom: 16px;
}

.page-subtitle {
    font-size: clamp(18px, 2vw, 24px);
    color: var(--slate-600);
}

/* ==================== Section ==================== */
.section {
    padding: 80px 0;
}

.section-white {
    background: white;
}

.section-slate {
    background: var(--slate-50);
}

.section-gradient {
    background: linear-gradient(135deg, #EFF6FF 0%, #FFFFFF 50%, #FFF7ED 100%);
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-header h2 {
    font-size: clamp(32px, 4vw, 48px);
    font-weight: 800;
    color: var(--slate-900);
    margin-bottom: 16px;
}

.section-header p {
    font-size: 20px;
    color: var(--slate-600);
}

/* ==================== 卡片网格 ==================== */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
}

.card {
    background: white;
    border-radius: 16px;
    padding: 32px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.card-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    margin-bottom: 16px;
}

.card h3 {
    font-size: 24px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 8px;
}

.card p {
    color: var(--slate-600);
    line-height: 1.6;
}

/* ==================== 功能详情卡片 ==================== */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 32px;
}

.feature-detail-card {
    background: white;
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.feature-detail-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.feature-detail-icon {
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    margin-bottom: 24px;
}

.feature-detail-card h3 {
    font-size: 28px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 12px;
}

.feature-detail-desc {
    color: var(--slate-600);
    line-height: 1.8;
    margin-bottom: 24px;
}

.feature-list {
    list-style: none;
}

.feature-list li {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 12px 0;
    color: var(--slate-700);
    border-bottom: 1px solid var(--slate-100);
}

.feature-list li:last-child {
    border-bottom: none;
}

.feature-list li span {
    color: var(--accent);
    font-weight: bold;
    flex-shrink: 0;
}

/* ==================== 使命愿景卡片 ==================== */
.mission-vision-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 48px;
}

.mission-vision-card {
    text-align: center;
    padding: 48px;
}

.mission-vision-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    margin: 0 auto 32px;
}

.mission-vision-card h3 {
    font-size: 32px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 16px;
}

.mission-vision-text {
    color: var(--slate-600);
    line-height: 2;
    font-size: 18px;
}

/* ==================== 团队卡片 ==================== */
.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
    margin-bottom: 64px;
}

.team-card {
    background: white;
    border-radius: 16px;
    padding: 40px;
    text-align: center;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.team-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.team-avatar {
    width: 120px;
    height: 120px;
    margin: 0 auto 24px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.team-avatar-placeholder {
    width: 120px;
    height: 120px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 48px;
    font-weight: bold;
}

.team-card h3 {
    font-size: 24px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 4px;
}

.team-role {
    color: var(--primary);
    font-weight: 600;
    margin-bottom: 16px;
}

.team-desc {
    color: var(--slate-600);
    line-height: 1.8;
    margin-bottom: 16px;
}

.team-education {
    color: var(--slate-700);
    font-size: 14px;
}

/* ==================== 团队统计 ==================== */
.team-summary {
    text-align: center;
    padding: 64px;
    background: white;
    border-radius: 16px;
}

.team-summary h3 {
    font-size: 32px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 32px;
}

.team-summary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 32px;
}

.team-summary-item {
    text-align: center;
}

.team-summary-number {
    font-size: 48px;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.team-summary-label {
    color: var(--slate-600);
    font-size: 16px;
}

/* ==================== 时间线 ==================== */
.timeline {
    max-width: 800px;
    margin: 0 auto;
}

.timeline-item {
    display: flex;
    gap: 32px;
    padding: 32px 0;
    border-bottom: 1px solid var(--slate-200);
}

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

.timeline-marker {
    flex-shrink: 0;
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 24px;
    font-weight: bold;
}

.timeline-content h3 {
    font-size: 24px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 8px;
}

.timeline-content p {
    color: var(--slate-600);
    line-height: 1.8;
}

/* ==================== 奖项卡片 ==================== */
.awards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
    margin-bottom: 64px;
}

.award-card {
    background: white;
    border-radius: 16px;
    padding: 40px;
    text-align: center;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.award-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.award-icon {
    font-size: 64px;
    margin-bottom: 24px;
}

.award-card h3 {
    font-size: 24px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 12px;
}

.award-card p {
    color: var(--slate-600);
    line-height: 1.8;
}

/* ==================== 成就统计 ==================== */
.achievements {
    text-align: center;
    padding: 64px;
    background: white;
    border-radius: 16px;
}

.achievements h3 {
    font-size: 32px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 32px;
}

.achievements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 32px;
}

.achievement-item {
    text-align: center;
}

.achievement-number {
    font-size: 48px;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.achievement-label {
    color: var(--slate-600);
    font-size: 16px;
}

/* ==================== CTA区域 ==================== */
.cta-section {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.cta-section h2 {
    font-size: clamp(32px, 4vw, 48px);
    font-weight: 800;
    color: var(--slate-900);
    margin-bottom: 16px;
}

.cta-section p {
    font-size: 20px;
    color: var(--slate-600);
    margin-bottom: 32px;
}

.cta-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

/* ==================== 联系页面 ==================== */
.contact-wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
}

.contact-info {
    background: white;
    border-radius: 16px;
    padding: 48px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.contact-info h2 {
    font-size: 36px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 16px;
}

.contact-intro {
    color: var(--slate-600);
    line-height: 1.8;
    margin-bottom: 32px;
}

.contact-items {
    margin-bottom: 32px;
}

.contact-item {
    display: flex;
    gap: 16px;
    padding: 24px 0;
    border-bottom: 1px solid var(--slate-100);
}

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

.contact-icon {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.contact-text h4 {
    font-size: 18px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 4px;
}

.contact-text p {
    color: var(--slate-600);
    line-height: 1.6;
}

.social-links {
    text-align: center;
}

.social-links h4 {
    font-size: 20px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 16px;
}

.social-icons {
    display: flex;
    gap: 16px;
    justify-content: center;
}

.social-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: var(--slate-100);
    border-radius: 50%;
    color: var(--slate-600);
    transition: all 0.3s ease;
}

.social-icon:hover {
    background: var(--primary);
    color: white;
    transform: translateY(-4px);
}

/* ==================== 联系表单 ==================== */
.contact-form-wrapper {
    background: white;
    border-radius: 16px;
    padding: 48px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.contact-form-wrapper h2 {
    font-size: 36px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 16px;
}

.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--slate-700);
    margin-bottom: 8px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--slate-200);
    border-radius: 8px;
    font-size: 16px;
    color: var(--slate-800);
    transition: all 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

/* ==================== FAQ ==================== */
.faq-list {
    max-width: 900px;
    margin: 0 auto;
}

.faq-item {
    background: white;
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 16px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    cursor: pointer;
    transition: all 0.3s ease;
}

.faq-item:hover {
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
}

.faq-question h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--slate-900);
    flex: 1;
}

.faq-icon {
    transition: transform 0.3s ease;
    flex-shrink: 0;
}

.faq-answer {
    display: none;
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--slate-100);
    color: var(--slate-600);
    line-height: 1.8;
}

/* ==================== 帮助中心 ==================== */
.search-container {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
    padding: 48px;
    background: white;
    border-radius: 16px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.search-container h2 {
    font-size: 32px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 24px;
}

.search-box {
    display: flex;
    gap: 12px;
}

.search-box input {
    flex: 1;
    padding: 16px 24px;
    border: 2px solid var(--slate-200);
    border-radius: 12px;
    font-size: 18px;
    transition: all 0.3s ease;
}

.search-box input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.help-categories {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.help-category-card {
    background: white;
    border-radius: 16px;
    padding: 32px;
    text-align: center;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
    display: block;
}

.help-category-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.help-category-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.help-category-card h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 8px;
}

.help-category-card p {
    color: var(--slate-600);
    margin-bottom: 16px;
}

.help-category-count {
    color: var(--primary);
    font-weight: 600;
}

.help-articles {
    max-width: 900px;
    margin: 0 auto;
}

.help-article {
    background: white;
    border-radius: 16px;
    padding: 32px;
    margin-bottom: 16px;
    display: flex;
    gap: 24px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
}

.help-article:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.help-article-number {
    flex-shrink: 0;
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 24px;
    font-weight: bold;
}

.help-article-content {
    flex: 1;
}

.help-article-content h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 8px;
}

.help-article-content p {
    color: var(--slate-600);
    line-height: 1.8;
    margin-bottom: 16px;
}

.help-article-link {
    color: var(--primary);
    font-weight: 600;
}

/* ==================== 视频卡片 ==================== */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.video-card {
    background: white;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    cursor: pointer;
}

.video-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.video-thumbnail {
    height: 180px;
    background: linear-gradient(135deg, var(--slate-800), var(--slate-900));
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.video-play {
    width: 64px;
    height: 64px;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    color: var(--slate-900);
    transition: all 0.3s ease;
}

.video-card:hover .video-play {
    transform: scale(1.1);
}

.video-card h3 {
    font-size: 18px;
    font-weight: 700;
    color: var(--slate-900);
    padding: 20px;
    margin-bottom: 4px;
}

.video-card > p {
    font-size: 14px;
    color: var(--slate-600);
    padding: 0 20px 20px;
}

.video-duration {
    font-size: 14px;
    color: var(--slate-500);
    padding: 0 20px 20px;
}

/* ==================== 支持CTA ==================== */
.support-cta {
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
    padding: 64px 48px;
    background: white;
    border-radius: 16px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.support-cta h2 {
    font-size: clamp(28px, 4vw, 40px);
    font-weight: 700;
    color: var(--slate-900);
    margin-bottom: 12px;
}

.support-cta p {
    font-size: 18px;
    color: var(--slate-600);
    margin-bottom: 32px;
}

.support-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 32px;
}

.support-info p {
    color: var(--slate-600);
    line-height: 1.8;
}

/* ==================== 页脚 ==================== */
.footer {
    background: var(--slate-900);
    color: white;
    padding: 64px 0 32px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 48px;
    margin-bottom: 48px;
}

.footer h4 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 24px;
}

.footer ul {
    list-style: none;
}

.footer li {
    margin-bottom: 12px;
}

.footer a {
    color: #8FA89F;
    transition: color 0.3s;
}

.footer a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 32px;
    text-align: center;
    color: #8FA89F;
}

/* ==================== 响应式设计 ==================== */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .page-header {
        padding: 120px 0 60px;
    }

    .card-grid,
    .feature-grid,
    .help-categories,
    .video-grid {
        grid-template-columns: 1fr;
    }

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

    .mission-vision-grid,
    .team-summary-grid,
    .achievements-grid {
        grid-template-columns: 1fr;
    }

    .cta-buttons,
    .support-actions {
        flex-direction: column;
    }

    .cta-buttons .btn,
    .support-actions .btn {
        width: 100%;
    }

    .search-box {
        flex-direction: column;
    }

    .timeline-item {
        flex-direction: column;
        text-align: center;
    }

    .timeline-marker {
        margin: 0 auto;
    }

    .help-article {
        flex-direction: column;
        text-align: center;
    }

    .help-article-number {
        margin: 0 auto;
    }
}