/* ==========================================
   CSS Reset & Base Styles
   ========================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2563eb;
    --secondary-color: #0ea5e9;
    --accent-color: #f59e0b;
    --dark-color: #1e293b;
    --light-color: #f8fafc;
    --text-color: #334155;
    --border-color: #e2e8f0;
    --success-color: #10b981;
    --gradient-1: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-2: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-3: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --gradient-primary: linear-gradient(135deg, #2563eb 0%, #0ea5e9 100%);
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 
                 'Microsoft YaHei', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: #ffffff;
    overflow-x: hidden;
}

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

section {
    padding: 80px 0;
}

/* ==========================================
   Navigation Bar
   ========================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all 0.3s ease;
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

.nav-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.logo i {
    font-size: 2rem;
}

.logo-text {
    font-size: 1.8rem;
}

.logo-subtitle {
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.7;
    font-weight: 400;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
    padding: 0.5rem 0;
}

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

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

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: var(--dark-color);
    transition: all 0.3s ease;
    border-radius: 2px;
}

/* ==========================================
   Hero Section
   ========================================== */
.hero {
    position: relative;
    height: 100vh;
    min-height: 600px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="100" height="100" patternUnits="userSpaceOnUse"><path d="M 100 0 L 0 0 0 100" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="1"/></pattern></defs><rect width="100%" height="100%" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.3);
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    color: white;
    max-width: 900px;
    padding: 0 20px;
}

.hero-title {
    font-size: 5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
    letter-spacing: 0.5rem;
}

.hero-subtitle {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
    font-weight: 300;
    letter-spacing: 0.3rem;
}

.hero-description {
    font-size: 1.3rem;
    margin-bottom: 3rem;
    line-height: 1.8;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    padding: 1rem 2.5rem;
    border: none;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

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

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 25px rgba(255, 255, 255, 0.3);
}

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

.btn-secondary:hover {
    background: white;
    color: var(--primary-color);
    transform: translateY(-3px);
}

.btn-full {
    width: 100%;
}

.scroll-indicator {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1;
}

.mouse {
    width: 26px;
    height: 40px;
    border: 2px solid white;
    border-radius: 15px;
    position: relative;
}

.wheel {
    width: 4px;
    height: 8px;
    background: white;
    border-radius: 2px;
    position: absolute;
    top: 8px;
    left: 50%;
    transform: translateX(-50%);
    animation: scroll 2s infinite;
}

@keyframes scroll {
    0% { opacity: 1; top: 8px; }
    100% { opacity: 0; top: 24px; }
}

/* Animations */
.animate-fade-in {
    animation: fadeIn 1s ease-in;
}

.animate-fade-in-delay {
    animation: fadeIn 1s ease-in 0.3s both;
}

.animate-fade-in-delay-2 {
    animation: fadeIn 1s ease-in 0.6s both;
}

.animate-fade-in-delay-3 {
    animation: fadeIn 1s ease-in 0.9s both;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ==========================================
   Section Headers
   ========================================== */
.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--dark-color);
    margin-bottom: 0.5rem;
}

.section-subtitle {
    font-size: 1.2rem;
    color: var(--text-color);
    opacity: 0.7;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.title-underline {
    width: 80px;
    height: 4px;
    background: var(--gradient-primary);
    margin: 1.5rem auto 0;
    border-radius: 2px;
}

/* ==========================================
   About Section
   ========================================== */
.about {
    background: var(--light-color);
}

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

.about-text h3 {
    font-size: 1.8rem;
    color: var(--dark-color);
    margin: 2rem 0 1rem;
}

.about-text h3:first-child {
    margin-top: 0;
}

.about-text p {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.stat-card {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease;
}

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

.stat-icon {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.stat-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--dark-color);
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: 1rem;
    color: var(--text-color);
    opacity: 0.8;
}

/* ==========================================
   Values Section
   ========================================== */
.values {
    background: white;
}

.values-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.value-card {
    padding: 2.5rem;
    border-radius: 15px;
    background: var(--light-color);
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.value-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-color);
}

.value-icon {
    font-size: 3.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.value-card h3 {
    font-size: 1.5rem;
    color: var(--dark-color);
    margin-bottom: 1rem;
}

.value-card p {
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-color);
}

/* ==========================================
   Research Section
   ========================================== */
.research {
    background: var(--light-color);
}

.research-list {
    display: grid;
    gap: 2.5rem;
}

.research-item {
    display: flex;
    gap: 2rem;
    background: white;
    padding: 2.5rem;
    border-radius: 15px;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
}

.research-item:hover {
    box-shadow: var(--shadow-xl);
    transform: translateX(10px);
}

.research-icon {
    flex-shrink: 0;
    width: 80px;
    height: 80px;
    background: var(--gradient-primary);
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    color: white;
}

.research-text h3 {
    font-size: 1.8rem;
    color: var(--dark-color);
    margin-bottom: 1rem;
}

.research-text p {
    font-size: 1.05rem;
    line-height: 1.8;
    color: var(--text-color);
    margin-bottom: 1.5rem;
}

.research-topics {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 0.8rem;
    list-style: none;
}

.research-topics li {
    padding: 0.6rem 1rem;
    background: var(--light-color);
    border-radius: 8px;
    font-size: 0.95rem;
    color: var(--text-color);
    border-left: 3px solid var(--primary-color);
}

/* ==========================================
   Ecosystem Section
   ========================================== */
.ecosystem {
    background: white;
}

.ecosystem-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2.5rem;
}

.ecosystem-card {
    padding: 2.5rem;
    background: var(--light-color);
    border-radius: 15px;
    transition: all 0.3s ease;
    border-top: 4px solid var(--primary-color);
}

.ecosystem-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
}

.eco-icon {
    width: 70px;
    height: 70px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: white;
    margin-bottom: 1.5rem;
}

.ecosystem-card h3 {
    font-size: 1.6rem;
    color: var(--dark-color);
    margin-bottom: 1rem;
}

.ecosystem-card p {
    font-size: 1.05rem;
    line-height: 1.7;
    color: var(--text-color);
    margin-bottom: 1.5rem;
}

.eco-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
}

.eco-tags span {
    padding: 0.4rem 1rem;
    background: white;
    border-radius: 20px;
    font-size: 0.9rem;
    color: var(--primary-color);
    border: 1px solid var(--border-color);
}

/* ==========================================
   News Section
   ========================================== */
.news {
    background: var(--light-color);
}

.news-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2.5rem;
}

.news-card {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    position: relative;
}

.news-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
}

.news-badge {
    position: absolute;
    top: 1rem;
    right: 1rem;
    padding: 0.4rem 1rem;
    background: var(--accent-color);
    color: white;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.news-date {
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.7;
    margin-bottom: 1rem;
}

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

.news-card p {
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-color);
    margin-bottom: 1.5rem;
}

.news-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: gap 0.3s ease;
}

.news-link:hover {
    gap: 1rem;
}

/* ==========================================
   Partners Section
   ========================================== */
.partners {
    background: white;
}

.partners-categories {
    display: grid;
    gap: 3rem;
}

.partner-category h3 {
    font-size: 1.5rem;
    color: var(--dark-color);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.partner-category h3 i {
    color: var(--primary-color);
}

.partner-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.partner-item {
    padding: 1.5rem;
    background: var(--light-color);
    border-radius: 10px;
    text-align: center;
    font-size: 1.1rem;
    color: var(--text-color);
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.partner-item:hover {
    background: white;
    border-color: var(--primary-color);
    transform: scale(1.05);
}

/* ==========================================
   Contact Section
   ========================================== */
.contact {
    background: var(--light-color);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 4rem;
}

.contact-info h3 {
    font-size: 1.8rem;
    color: var(--dark-color);
    margin-bottom: 2rem;
}

.contact-item {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.contact-item i {
    font-size: 1.8rem;
    color: var(--primary-color);
    flex-shrink: 0;
}

.contact-item h4 {
    font-size: 1.2rem;
    color: var(--dark-color);
    margin-bottom: 0.5rem;
}

.contact-item p {
    font-size: 1rem;
    color: var(--text-color);
    line-height: 1.6;
}

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
}

.social-link {
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.3rem;
    text-decoration: none;
    transition: transform 0.3s ease;
}

.social-link:hover {
    transform: scale(1.15) rotate(5deg);
}

.contact-form-wrapper h3 {
    font-size: 1.8rem;
    color: var(--dark-color);
    margin-bottom: 2rem;
}

.contact-form {
    background: white;
    padding: 2.5rem;
    border-radius: 15px;
    box-shadow: var(--shadow-md);
}

.form-group {
    position: relative;
    margin-bottom: 2rem;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.3s ease;
    background: white;
}

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

.form-group label {
    position: absolute;
    top: 1rem;
    left: 1rem;
    color: var(--text-color);
    opacity: 0.6;
    pointer-events: none;
    transition: all 0.3s ease;
    background: white;
    padding: 0 0.3rem;
}

.form-group input:focus + label,
.form-group textarea:focus + label,
.form-group select:focus + label,
.form-group input:not(:placeholder-shown) + label,
.form-group textarea:not(:placeholder-shown) + label,
.form-group select:valid + label {
    top: -0.6rem;
    left: 0.8rem;
    font-size: 0.85rem;
    color: var(--primary-color);
}

/* ==========================================
   Footer
   ========================================== */
.footer {
    background: var(--dark-color);
    color: white;
    padding: 4rem 0 2rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.footer-logo i {
    font-size: 2rem;
}

.footer-section p {
    line-height: 1.8;
    opacity: 0.8;
}

.footer-section h4 {
    font-size: 1.3rem;
    margin-bottom: 1.5rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.8rem;
}

.footer-section ul li a {
    color: white;
    text-decoration: none;
    opacity: 0.8;
    transition: opacity 0.3s ease;
}

.footer-section ul li a:hover {
    opacity: 1;
    text-decoration: underline;
}

.footer-social {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.footer-social a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.1rem;
    text-decoration: none;
    transition: background 0.3s ease;
}

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

.footer-subscribe {
    margin-bottom: 1rem;
    opacity: 0.8;
}

.footer-subscribe-form {
    display: flex;
    gap: 0.5rem;
}

.footer-subscribe-form input {
    flex: 1;
    padding: 0.8rem;
    border: none;
    border-radius: 5px;
    font-size: 0.95rem;
}

.footer-subscribe-form button {
    padding: 0.8rem 1.2rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.3s ease;
}

.footer-subscribe-form button:hover {
    background: var(--secondary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    opacity: 0.7;
}

.footer-bottom p {
    margin-bottom: 0.5rem;
}

.footer-bottom a {
    color: white;
    text-decoration: none;
    margin: 0 0.5rem;
}

.footer-bottom a:hover {
    text-decoration: underline;
}

/* ==========================================
   Back to Top Button
   ========================================== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 1.3rem;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-5px);
}

/* ==========================================
   Responsive Design
   ========================================== */
@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: white;
        flex-direction: column;
        padding: 2rem;
        transition: left 0.3s ease;
        box-shadow: var(--shadow-lg);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .hero-title {
        font-size: 3rem;
    }
    
    .hero-subtitle {
        font-size: 1.5rem;
    }
    
    .hero-description {
        font-size: 1.1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .about-stats,
    .values-grid,
    .ecosystem-grid,
    .news-grid {
        grid-template-columns: 1fr;
    }
    
    .research-item {
        flex-direction: column;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        width: 100%;
    }
    
    .btn {
        width: 100%;
    }
    
    section {
        padding: 50px 0;
    }
}