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

:root {
    /* 品牌色彩 */
    --primary-blue: #1a365d;
    --secondary-orange: #ed8936;
    --accent-cyan: #00d4ff;
    --light-bg: #ffffff;
    --lighter-bg: #f8fafc;
    --dark-text: #1a202c;
    --gray-text: #4a5568;
    --border-color: #e2e8f0;
    
    /* 字体 */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    
    /* 间距 */
    --container-padding: 0 3rem;
    --section-padding: 5rem 0;
}

body {
    font-family: var(--font-family);
    background: linear-gradient(135deg, var(--light-bg) 0%, var(--lighter-bg) 100%);
    color: var(--dark-text);
    line-height: 1.6;
    overflow-x: hidden;
    margin: 0;
    padding: 0 1rem;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--container-padding);
}

/* Logo样式 */
.logo {
    display: flex;
    flex-direction: column;
    align-items: center;
    font-weight: 700;
}

.logo-main {
    font-size: 1.5rem;
    background: linear-gradient(45deg, var(--accent-cyan), var(--secondary-orange));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: 2px;
}

.logo-sub {
    font-size: 0.7rem;
    color: var(--gray-text);
    letter-spacing: 1px;
    margin-top: -2px;
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    padding: 1rem 0;
}

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

.nav-menu {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    color: var(--dark-text);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-blue);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-blue);
    transition: width 0.3s ease;
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.lang-switch {
    background: var(--primary-blue);
    color: var(--light-bg) !important;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-weight: 600;
}

.lang-switch:hover {
    background: var(--secondary-orange);
    color: var(--light-bg) !important;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: var(--dark-text);
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero区域 */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding-top: 80px;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
}

.particles {
    position: absolute;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 80%, rgba(0, 212, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(237, 137, 54, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(26, 54, 93, 0.1) 0%, transparent 50%);
    animation: float 20s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(180deg); }
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    position: relative;
    z-index: 2;
}

.hero-title {
    margin-bottom: 1.5rem;
}

.title-cn {
    display: block;
    font-size: 3.5rem;
    font-weight: 700;
    background: linear-gradient(45deg, var(--accent-cyan), var(--secondary-orange));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
}

.title-en {
    display: block;
    font-size: 1.5rem;
    color: var(--primary-blue);
    font-weight: 400;
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--secondary-orange);
    margin-bottom: 1.5rem;
    font-weight: 500;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--gray-text);
    margin-bottom: 2rem;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: 4rem;
}

.btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: 50px;
    font-weight: 600;
    text-decoration: none;
    display: inline-block;
    transition: all 0.3s ease;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: linear-gradient(45deg, var(--accent-cyan), var(--secondary-orange));
    color: var(--light-text);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0, 212, 255, 0.3);
}

.btn-secondary {
    background: transparent;
    color: var(--primary-blue);
    border: 2px solid var(--primary-blue);
}

.btn-secondary:hover {
    background: var(--primary-blue);
    color: var(--light-bg);
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.1rem;
    font-weight: 600;
}

.hero-email-cta {
    margin-top: 3rem;
    display: flex;
    justify-content: center;
}

.email-cta-card {
    background: linear-gradient(135deg, rgba(26, 54, 93, 0.95) 0%, rgba(255, 165, 0, 0.95) 100%);
    color: white;
    padding: 2rem;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    border: 2px solid rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    max-width: 500px;
    animation: float 3s ease-in-out infinite;
}

.email-cta-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: white;
}

.email-cta-card p {
    margin-bottom: 2rem;
    line-height: 1.6;
    opacity: 0.9;
}

.email-cta-card .btn {
    background: white;
    color: var(--primary-blue);
    border: none;
    font-weight: 600;
    transition: all 0.3s ease;
}

.email-cta-card .btn:hover {
    background: var(--secondary-orange);
    color: white;
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(255, 165, 0, 0.4);
}

/* Hero视觉元素 */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.logo-large {
    position: relative;
}

.logo-circle {
    width: 300px;
    height: 300px;
    border-radius: 50%;
    background: linear-gradient(45deg, var(--primary-blue), var(--accent-cyan));
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: relative;
    animation: pulse 3s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.logo-text {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--light-bg);
    letter-spacing: 3px;
}

.logo-icon {
    font-size: 3rem;
    margin-top: 1rem;
}

/* 通用标题样式 */
.section-title {
    font-size: 2.8rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 1.5rem;
    background: linear-gradient(45deg, var(--accent-cyan), var(--secondary-orange));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
}

.section-subtitle {
    text-align: center;
    color: var(--gray-text);
    font-size: 1.3rem;
    margin-bottom: 4rem;
    line-height: 1.6;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* 特色亮点 */
.features {
    padding: calc(var(--section-padding) + 2rem);
    background: rgba(26, 54, 93, 0.08);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2.5rem;
    margin-top: 4rem;
}

.feature-card {
    background: var(--light-bg);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 2.5rem 2rem;
    text-align: center;
    transition: all 0.4s ease;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-blue), var(--secondary-orange));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 212, 255, 0.15);
}

.feature-card:hover::before {
    transform: scaleX(1);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: var(--primary-blue);
}

.feature-card p {
    color: var(--gray-text);
    line-height: 1.6;
}

/* 关于我们 */
.about {
    padding: calc(var(--section-padding) + 3rem);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 5rem;
    align-items: center;
    margin-top: 2rem;
}

.about-description {
    font-size: 1.1rem;
    color: var(--gray-text);
    line-height: 1.8;
    margin-bottom: 2rem;
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2.5rem;
    margin: 3rem 0;
}

.stat {
    text-align: center;
    padding: 2rem 1.5rem;
    background: var(--light-bg);
    border-radius: 15px;
    border: 1px solid var(--border-color);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    position: relative;
    overflow: hidden;
}

.stat::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-cyan), var(--secondary-orange));
}

.stat:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px rgba(0, 212, 255, 0.15);
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-blue);
    margin-bottom: 0.5rem;
}

.stat-label {
    color: var(--gray-text);
    font-size: 0.9rem;
}

.ai-teaching-explanation {
    margin-top: 2rem;
    padding: 2rem;
    background: var(--lighter-bg);
    border-radius: 12px;
    border-left: 4px solid var(--accent-cyan);
}

.ai-teaching-explanation h3 {
    color: var(--primary-blue);
    font-size: 1.3rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.ai-teaching-explanation p {
    color: var(--gray-text);
    margin-bottom: 1rem;
    line-height: 1.7;
}

.ai-teaching-explanation ul {
    margin: 1rem 0;
    padding-left: 1.5rem;
}

.ai-teaching-explanation li {
    color: var(--gray-text);
    margin-bottom: 0.8rem;
    line-height: 1.6;
}

.ai-teaching-explanation li strong {
    color: var(--primary-blue);
}

.africa-map {
    width: 100%;
    height: 300px;
    background: linear-gradient(45deg, var(--primary-blue), var(--secondary-orange));
    border-radius: 15px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

.burundi-highlight {
    background: var(--accent-cyan);
    color: var(--dark-bg);
    padding: 1rem 2rem;
    border-radius: 25px;
    font-weight: 600;
    font-size: 1.2rem;
    animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

/* 课程体系 */
.courses {
    padding: calc(var(--section-padding) + 2rem);
    background: rgba(237, 137, 54, 0.06);
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2.5rem;
    margin-top: 4rem;
}

.course-category {
    background: var(--light-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2.5rem 2rem;
    transition: all 0.4s ease;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
    position: relative;
    overflow: hidden;
}

.course-category::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--secondary-orange), var(--accent-cyan));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.course-category:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(237, 137, 54, 0.15);
}

.course-category:hover::before {
    transform: scaleX(1);
}

.course-category h3 {
    color: var(--secondary-orange);
    font-size: 1.3rem;
    margin-bottom: 1.5rem;
    text-align: center;
}

.course-category ul {
    list-style: none;
}

.course-category li {
    padding: 0.5rem 0;
    color: var(--gray-text);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.course-category li:last-child {
    border-bottom: none;
}

.course-category li::before {
    content: '▸';
    color: var(--primary-blue);
    margin-right: 0.5rem;
}

/* 新闻动态 */
.news {
    padding: calc(var(--section-padding) + 2rem);
    background: var(--lighter-bg);
}

.news-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2.5rem;
    margin-top: 4rem;
}

.news-card {
    background: var(--light-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2.5rem 2rem;
    transition: all 0.4s ease;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
    position: relative;
    overflow: hidden;
}

.news-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-blue), var(--secondary-orange));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.news-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 212, 255, 0.15);
}

.news-card:hover::before {
    transform: scaleX(1);
}

.news-date {
    color: var(--secondary-orange);
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.news-card h3 {
    color: var(--primary-blue);
    font-size: 1.3rem;
    margin-bottom: 1rem;
    line-height: 1.4;
}

.news-card p {
    color: var(--gray-text);
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.news-tag {
    display: inline-block;
    background: var(--primary-blue);
    color: var(--light-bg);
    padding: 0.3rem 0.8rem;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 500;
}

/* 常见问题 */
.faq {
    padding: var(--section-padding);
}

.faq-list {
    max-width: 800px;
    margin: 3rem auto 0;
}

.faq-item {
    background: var(--light-bg);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    margin-bottom: 1rem;
    overflow: hidden;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.faq-question:hover {
    background: var(--lighter-bg);
}

.faq-question h3 {
    color: var(--primary-blue);
    font-size: 1.1rem;
    margin: 0;
    flex: 1;
}

.faq-toggle {
    color: var(--secondary-orange);
    font-size: 1.5rem;
    font-weight: bold;
    transition: transform 0.3s ease;
}

.faq-item.active .faq-toggle {
    transform: rotate(45deg);
}

.faq-answer {
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
}

.faq-item.active .faq-answer {
    padding: 0 1.5rem 1.5rem;
    max-height: 200px;
}

.faq-answer p {
    color: var(--gray-text);
    line-height: 1.6;
    margin: 0;
}

/* 申请入学 */
.apply {
    padding: var(--section-padding);
}

.email-register {
    text-align: center;
    padding: 2rem;
    background: var(--light-bg);
    border: 1px solid var(--border-color);
    border-radius: 15px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.email-register h3 {
    color: var(--primary-blue);
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.email-register p {
    color: var(--gray-text);
    margin-bottom: 2rem;
}

.register-button {
    margin-bottom: 2rem;
}

.btn-icon {
    margin-right: 0.5rem;
}

.register-note {
    text-align: left;
    background: var(--lighter-bg);
    padding: 1.5rem;
    border-radius: 10px;
    border-left: 4px solid var(--primary-blue);
}

.register-note p {
    margin-bottom: 1rem;
    color: var(--dark-text);
    font-weight: 500;
}

.register-note ul {
    list-style: none;
    padding: 0;
}

.register-note li {
    padding: 0.3rem 0;
    color: var(--gray-text);
    position: relative;
    padding-left: 1.2rem;
}

.register-note li::before {
    content: '•';
    color: var(--primary-blue);
    position: absolute;
    left: 0;
    font-weight: bold;
}

.apply-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    margin-top: 3rem;
}

.apply-info h3 {
    color: var(--primary-blue);
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
}

.apply-info ul {
    list-style: none;
    margin-bottom: 2rem;
}

.apply-info li {
    padding: 0.5rem 0;
    color: var(--gray-text);
    position: relative;
    padding-left: 1.5rem;
}

.apply-info li::before {
    content: '✓';
    color: var(--secondary-orange);
    position: absolute;
    left: 0;
    font-weight: bold;
}

.email-info {
    background: rgba(26, 54, 93, 0.1);
    border: 1px solid var(--primary-blue);
    border-radius: 10px;
    padding: 1.5rem;
}

.email-info h4 {
    color: var(--primary-blue);
    margin-bottom: 0.5rem;
}

.email-info p {
    color: var(--gray-text);
}

/* 表单样式 */
.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--dark-text);
    font-weight: 500;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 1rem;
    background: var(--light-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--dark-text);
    font-family: var(--font-family);
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-blue);
}

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

/* 联系我们 */
.contact {
    padding: var(--section-padding);
    background: rgba(26, 54, 93, 0.1);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    margin-top: 3rem;
}

.contact-info h3 {
    color: var(--primary-blue);
    font-size: 1.5rem;
    margin-bottom: 2rem;
}

.contact-item {
    display: flex;
    align-items: center;
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: var(--light-bg);
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.contact-icon {
    font-size: 1.5rem;
    margin-right: 1rem;
}

.contact-form h3 {
    color: var(--primary-blue);
    font-size: 1.5rem;
    margin-bottom: 2rem;
}

/* 页脚 */
.footer {
    background: var(--lighter-bg);
    border-top: 1px solid var(--border-color);
    padding: 3rem 0 1rem;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 3rem;
    margin-bottom: 2rem;
}

.footer-logo p {
    color: var(--gray-text);
    margin-top: 1rem;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
}

.footer-section h4 {
    color: var(--primary-blue);
    margin-bottom: 1rem;
}

.footer-section a,
.footer-section p {
    display: block;
    color: var(--gray-text);
    text-decoration: none;
    margin-bottom: 0.5rem;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: var(--primary-blue);
}

.footer-bottom {
    border-top: 1px solid var(--border-color);
    padding-top: 1rem;
    text-align: center;
    color: var(--gray-text);
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--lighter-bg);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-blue);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-orange);
}

/* 新增链接样式 */
.feature-link {
    display: inline-block;
    color: var(--primary-blue);
    text-decoration: none;
    font-weight: 500;
    margin-top: 1rem;
    padding: 0.5rem 1rem;
    border: 1px solid var(--primary-blue);
    border-radius: 6px;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.feature-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.feature-link:hover::before {
    left: 100%;
}

.feature-link:hover {
    background: var(--primary-blue);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(26, 54, 93, 0.3);
}

.about-links {
    margin-top: 2rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.about-link {
    color: var(--primary-blue);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.about-link:hover {
    color: var(--secondary-orange);
    text-decoration: underline;
}

.course-links {
    margin-top: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.course-link {
    color: var(--primary-blue);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.3s ease;
}

.course-link:hover {
    color: var(--secondary-orange);
    text-decoration: underline;
}

.news-link {
    display: inline-block;
    color: var(--primary-blue);
    text-decoration: none;
    font-weight: 500;
    margin-top: 1rem;
    transition: color 0.3s ease;
}

.news-link:hover {
    color: var(--secondary-orange);
    text-decoration: underline;
}

.contact-links {
    margin-top: 2rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.contact-link {
    color: var(--primary-blue);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.contact-link:hover {
    color: var(--secondary-orange);
    text-decoration: underline;
}

.footer-social {
    margin-top: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer-social a {
    color: var(--gray-text);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-social a:hover {
    color: var(--primary-blue);
}

/* 资源中心页面样式 */
.page-header {
    padding: 6rem 0 4rem;
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-orange) 100%);
    color: white;
    text-align: center;
}

.page-header .section-title {
    color: white;
    margin-bottom: 1rem;
}

.page-header .section-subtitle {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.2rem;
}

.resources-section {
    padding: var(--section-padding);
}

.resources-section:nth-child(even) {
    background: rgba(26, 54, 93, 0.05);
}

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.resource-card {
    background: var(--light-bg);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
}

.resource-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.resource-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    display: block;
}

.resource-card h3 {
    color: var(--primary-blue);
    font-size: 1.5rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.resource-card p {
    color: var(--gray-text);
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.resource-links {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.resource-link {
    color: var(--primary-blue);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 0;
    transition: color 0.3s ease;
    border-bottom: 1px solid transparent;
}

.resource-link:hover {
    color: var(--secondary-orange);
    border-bottom-color: var(--secondary-orange);
}

/* AI教育理念样式 */
.ai-philosophy {
    padding: calc(var(--section-padding) + 3rem);
    background: linear-gradient(135deg, rgba(26, 54, 93, 0.06) 0%, rgba(255, 165, 0, 0.06) 100%);
}

.philosophy-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 5rem;
    margin-top: 4rem;
    align-items: center;
}

.philosophy-text {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.philosophy-item {
    background: var(--light-bg);
    padding: 2.5rem 2rem;
    border-radius: 16px;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
    transition: all 0.4s ease;
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.philosophy-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent-cyan), var(--secondary-orange));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.philosophy-item:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 212, 255, 0.15);
}

.philosophy-item:hover::before {
    transform: scaleX(1);
}

.philosophy-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    display: block;
}

.philosophy-item h3 {
    color: var(--primary-blue);
    font-size: 1.3rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.philosophy-item p {
    color: var(--gray-text);
    line-height: 1.6;
}

.philosophy-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.ai-learning-cycle {
    position: relative;
    width: 300px;
    height: 300px;
    border: 3px solid var(--primary-blue);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    animation: rotate 20s linear infinite;
}

.ai-learning-cycle::before {
    content: '';
    position: absolute;
    width: 250px;
    height: 250px;
    border: 2px solid var(--secondary-orange);
    border-radius: 50%;
    animation: rotate 15s linear infinite reverse;
}

.ai-learning-cycle::after {
    content: '';
    position: absolute;
    width: 200px;
    height: 200px;
    border: 1px solid var(--primary-blue);
    border-radius: 50%;
    animation: rotate 10s linear infinite;
}

.cycle-step {
    position: absolute;
    display: flex;
    flex-direction: column;
    align-items: center;
    background: var(--light-bg);
    padding: 1rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    border: 1px solid var(--border-color);
}

.cycle-step:nth-child(1) {
    top: -20px;
    left: 50%;
    transform: translateX(-50%);
}

.cycle-step:nth-child(2) {
    top: 50%;
    right: -20px;
    transform: translateY(-50%);
}

.cycle-step:nth-child(3) {
    bottom: -20px;
    left: 50%;
    transform: translateX(-50%);
}

.cycle-step:nth-child(4) {
    top: 50%;
    left: -20px;
    transform: translateY(-50%);
}

.step-number {
    background: var(--primary-blue);
    color: white;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.step-text {
    font-size: 0.9rem;
    color: var(--dark-text);
    font-weight: 500;
}

@keyframes rotate {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

/* 技术架构样式 */
.tech-architecture {
    padding: var(--section-padding);
    background: linear-gradient(135deg, rgba(26, 54, 93, 0.08) 0%, rgba(255, 165, 0, 0.08) 100%);
}

.tech-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    margin-top: 3rem;
    align-items: start;
}

.tech-overview {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.tech-item {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
}

.tech-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.tech-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    display: block;
}

.tech-item h3 {
    color: var(--primary-blue);
    font-size: 1.3rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.tech-item p {
    color: var(--gray-text);
    line-height: 1.6;
}

.tech-stack {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    border: 1px solid var(--border-color);
}

.tech-stack h3 {
    color: var(--primary-blue);
    font-size: 1.5rem;
    margin-bottom: 2rem;
    text-align: center;
}

.stack-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.stack-item {
    background: var(--lighter-bg);
    padding: 1rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.stack-item:hover {
    background: var(--primary-blue);
    color: white;
    transform: translateY(-2px);
}

.stack-name {
    display: block;
    font-weight: 600;
    margin-bottom: 0.3rem;
}

.stack-desc {
    display: block;
    font-size: 0.9rem;
    opacity: 0.8;
}

/* 全球影响样式 */
.global-impact {
    padding: var(--section-padding);
    background: linear-gradient(135deg, rgba(26, 54, 93, 0.1) 0%, rgba(255, 165, 0, 0.1) 100%);
}

.impact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    margin-top: 3rem;
    align-items: center;
}

.impact-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.impact-stat {
    text-align: center;
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
}

.impact-stat:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.stat-circle {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-orange) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem;
    color: white;
    font-size: 1.5rem;
    font-weight: bold;
    box-shadow: 0 4px 15px rgba(26, 54, 93, 0.3);
}

.impact-stat h3 {
    color: var(--primary-blue);
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.impact-stat p {
    color: var(--gray-text);
    font-size: 0.9rem;
    line-height: 1.5;
}

.impact-map {
    display: flex;
    justify-content: center;
    align-items: center;
}

.world-map {
    position: relative;
    width: 400px;
    height: 300px;
    background: linear-gradient(135deg, #e3f2fd 0%, #fff3e0 100%);
    border-radius: 20px;
    border: 2px solid var(--primary-blue);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

.map-point {
    position: absolute;
    width: 12px;
    height: 12px;
    background: var(--secondary-orange);
    border-radius: 50%;
    border: 2px solid white;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    animation: pulse 2s infinite;
}

.map-point.burundi {
    background: var(--primary-blue);
    width: 16px;
    height: 16px;
    animation: pulse 1.5s infinite;
}

.point-label {
    position: absolute;
    top: -30px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--light-bg);
    padding: 0.3rem 0.6rem;
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--dark-text);
    white-space: nowrap;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.map-point:hover .point-label {
    opacity: 1;
}

@keyframes pulse {
    0% {
        transform: scale(1);
        box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    }
    50% {
        transform: scale(1.2);
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
    }
    100% {
        transform: scale(1);
        box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--light-bg);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 2rem 0;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-toggle {
        display: block;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .about-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .news-grid {
        grid-template-columns: 1fr;
    }
    
    .apply-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }
    
    .resources-grid {
        grid-template-columns: 1fr;
    }
    
    /* AI教育理念响应式 */
    .philosophy-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .philosophy-text {
        grid-template-columns: 1fr;
    }
    
    .ai-learning-cycle {
        width: 250px;
        height: 250px;
    }
    
    .ai-learning-cycle::before {
        width: 200px;
        height: 200px;
    }
    
    .ai-learning-cycle::after {
        width: 150px;
        height: 150px;
    }
    
    /* 技术架构响应式 */
    .tech-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .tech-overview {
        grid-template-columns: 1fr;
    }
    
    .stack-grid {
        grid-template-columns: 1fr;
    }
    
    /* 全球影响响应式 */
    .impact-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .impact-stats {
        grid-template-columns: 1fr;
    }
    
    .world-map {
        width: 300px;
        height: 200px;
    }
    
    .map-point {
        width: 10px;
        height: 10px;
    }
    
    .map-point.burundi {
        width: 14px;
        height: 14px;
    }
    
    .point-label {
        font-size: 0.7rem;
        padding: 0.2rem 0.4rem;
    }
    
    /* 未来愿景响应式 */
    .vision-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .vision-timeline {
        grid-template-columns: 1fr;
    }
    
    .timeline-item {
        flex-direction: column;
        text-align: center;
    }
    
    .timeline-marker {
        margin-bottom: 1rem;
    }
    
    .vision-goals {
        grid-template-columns: 1fr;
    }
    
    .articles-grid {
        gap: 2rem;
    }
    
    .article-card {
        padding: 1.5rem;
    }
    
    .article-title {
        font-size: 1.5rem;
    }
    
    .article-meta {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .email-cta-card {
        margin: 0 1rem;
        padding: 1.5rem;
    }
    
    .email-cta-card h3 {
        font-size: 1.3rem;
    }
}

/* 未来愿景样式 */
.future-vision {
    padding: var(--section-padding);
    background: linear-gradient(135deg, rgba(26, 54, 93, 0.12) 0%, rgba(255, 165, 0, 0.12) 100%);
}

.vision-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    margin-top: 3rem;
    align-items: start;
}

.vision-timeline {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.timeline-item {
    display: flex;
    align-items: center;
    gap: 2rem;
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
    position: relative;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: linear-gradient(to bottom, var(--primary-blue), var(--secondary-orange));
    border-radius: 2px;
}

.timeline-item:hover {
    transform: translateX(10px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.timeline-marker {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-orange) 100%);
    color: white;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.2rem;
    flex-shrink: 0;
    box-shadow: 0 4px 15px rgba(26, 54, 93, 0.3);
}

.timeline-content h3 {
    color: var(--primary-blue);
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.timeline-content p {
    color: var(--gray-text);
    line-height: 1.6;
}

.vision-goals {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.goal-item {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
    text-align: center;
}

.goal-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.goal-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    display: block;
}

.goal-item h3 {
    color: var(--primary-blue);
    font-size: 1.3rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.goal-item p {
    color: var(--gray-text);
    line-height: 1.6;
}

/* 文章页面样式 */
.articles-section {
    padding: var(--section-padding);
    background: var(--lighter-bg);
}

.articles-grid {
    display: grid;
    gap: 3rem;
    max-width: 800px;
    margin: 0 auto;
}

.article-card {
    background: var(--light-bg);
    border-radius: 15px;
    padding: 2.5rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.article-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 212, 255, 0.15);
}

.article-meta {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
}

.article-date {
    color: var(--gray-text);
    background: var(--lighter-bg);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
}

.article-category {
    color: var(--primary-blue);
    background: rgba(26, 54, 93, 0.1);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-weight: 600;
}

.article-title {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-blue);
    margin-bottom: 1rem;
    line-height: 1.3;
}

.article-excerpt {
    font-size: 1.1rem;
    color: var(--gray-text);
    line-height: 1.6;
    margin-bottom: 2rem;
    font-style: italic;
}

.article-content {
    margin-bottom: 2rem;
}

.article-content h3 {
    font-size: 1.3rem;
    color: var(--primary-blue);
    margin: 1.5rem 0 1rem 0;
    font-weight: 600;
}

.article-content p {
    color: var(--gray-text);
    line-height: 1.7;
    margin-bottom: 1rem;
}

.article-content ul {
    margin: 1rem 0;
    padding-left: 1.5rem;
}

.article-content li {
    color: var(--gray-text);
    margin-bottom: 0.8rem;
    line-height: 1.6;
}

.article-content li strong {
    color: var(--primary-blue);
}

.article-tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.tag {
    background: linear-gradient(45deg, var(--accent-cyan), var(--secondary-orange));
    color: white;
    padding: 0.4rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    transition: transform 0.2s ease;
}

.tag:hover {
    transform: scale(1.05);
}

/* 悬浮邮箱申请按钮 */
.floating-email-btn {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 1000;
    cursor: pointer;
    transition: all 0.3s ease;
    animation: float 3s ease-in-out infinite;
}

.floating-email-btn:hover {
    transform: translateY(-5px) scale(1.05);
}

.floating-btn-content {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-orange) 100%);
    color: white;
    padding: 1rem 1.5rem;
    border-radius: 50px;
    box-shadow: 0 8px 25px rgba(26, 54, 93, 0.3);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    font-size: 1rem;
    border: 2px solid rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    transition: all 0.3s ease;
}

.floating-btn-content:hover {
    box-shadow: 0 12px 35px rgba(255, 165, 0, 0.4);
    transform: scale(1.05);
}

.floating-icon {
    font-size: 1.2rem;
}

.floating-text {
    white-space: nowrap;
}

.floating-tooltip {
    position: absolute;
    bottom: 100%;
    right: 0;
    background: rgba(0, 0, 0, 0.9);
    color: white;
    padding: 0.8rem 1rem;
    border-radius: 8px;
    font-size: 0.9rem;
    white-space: nowrap;
    margin-bottom: 10px;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    transform: translateY(10px);
}

.floating-tooltip::after {
    content: '';
    position: absolute;
    top: 100%;
    right: 20px;
    border: 6px solid transparent;
    border-top-color: rgba(0, 0, 0, 0.9);
}

.floating-email-btn:hover .floating-tooltip {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

/* 移动端悬浮按钮适配 */
@media (max-width: 768px) {
    .floating-email-btn {
        bottom: 20px;
        right: 20px;
    }
    
    .floating-btn-content {
        padding: 0.8rem 1.2rem;
        font-size: 0.9rem;
    }
    
    .floating-text {
        display: none;
    }
    
    .floating-tooltip {
        display: none;
    }
}