:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --accent: #7c3aed;
    --accent-light: #ede9fe;
    --text: #1f2937;
    --text-light: #6b7280;
    --bg: #ffffff;
    --bg-alt: #f8fafc;
    --bg-dark: #0f172a;
    --border: #e2e8f0;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    --radius: 12px;
    --radius-lg: 20px;
    --max-width: 1200px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
    line-height: 1.7;
    color: var(--text);
    background: var(--bg);
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* Header */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    transition: box-shadow 0.3s ease;
}

.site-header.scrolled {
    box-shadow: var(--shadow);
}

.site-header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text);
    font-weight: 700;
    font-size: 1.1rem;
}

.logo-img {
    width: auto;
    height: 40px;
    border-radius: 8px;
    display: block;
}

.logo-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    border-radius: 10px;
    font-size: 1.25rem;
    font-weight: 800;
}

.main-nav {
    display: flex;
    align-items: center;
}

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

.nav-list a {
    text-decoration: none;
    color: var(--text);
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.2s ease;
    position: relative;
}

.nav-list a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: width 0.2s ease;
}

.nav-list a:hover {
    color: var(--primary);
}

.nav-list a:hover::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text);
    transition: all 0.3s ease;
}

/* Hero */
.hero {
    position: relative;
    padding: 150px 0 90px;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    color: white;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(circle at 20% 30%, rgba(37, 99, 235, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(124, 58, 237, 0.15) 0%, transparent 50%);
    pointer-events: none;
}

.hero .container {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 60px;
    align-items: center;
}

.hero-subtitle {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 50px;
    font-size: 0.9rem;
    font-weight: 500;
    letter-spacing: 1px;
    margin-bottom: 24px;
}

.hero h1 {
    font-size: 3.2rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 24px;
    background: linear-gradient(to right, #fff, #cbd5e1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.15rem;
    color: #cbd5e1;
    max-width: 600px;
    margin-bottom: 36px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 28px;
    border-radius: 50px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    box-shadow: 0 10px 20px -5px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 14px 28px -5px rgba(37, 99, 235, 0.5);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.2);
}

.hero-visual {
    display: flex;
    flex-direction: column;
    gap: 24px;
    align-items: stretch;
    width: 320px;
}

.hero-logo {
    background: white;
    padding: 28px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    width: 100%;
}

.hero-logo img {
    width: 100%;
    height: auto;
    display: block;
}

.hero-stats {
    display: flex;
    flex-direction: row;
    gap: 12px;
    width: 100%;
}

.stat-item {
    display: flex;
    align-items: baseline;
    justify-content: center;
    flex: 1;
    gap: 6px;
    padding: 16px 20px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius);
    backdrop-filter: blur(10px);
}

.stat-number {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 1.1rem;
    color: #94a3b8;
    font-weight: 500;
}

/* Sections */
.section {
    padding: 100px 0;
}

.section-header {
    max-width: 720px;
    margin: 0 auto 60px;
    text-align: center;
}

.section-header.light {
    color: white;
}

.section-tag {
    display: inline-block;
    padding: 4px 12px;
    background: var(--primary-light);
    color: var(--primary-dark);
    border-radius: 50px;
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 1px;
    margin-bottom: 16px;
}

.section-header.light .section-tag {
    background: rgba(255, 255, 255, 0.15);
    color: white;
}

.section-header h2 {
    font-size: 2.4rem;
    font-weight: 800;
    margin-bottom: 16px;
    line-height: 1.3;
}

.section-header p {
    font-size: 1.1rem;
    color: var(--text-light);
}

.section-header.light p {
    color: rgba(255, 255, 255, 0.8);
}

/* About */
.about {
    background: var(--bg-alt);
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.about-card {
    background: white;
    padding: 32px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.about-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.about-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.about-card h3 {
    font-size: 1.2rem;
    margin-bottom: 12px;
    color: var(--text);
}

.about-card p {
    color: var(--text-light);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* History */
.history {
    background: var(--bg-dark);
    color: white;
    position: relative;
    overflow: hidden;
}

.history::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(circle at 10% 20%, rgba(37, 99, 235, 0.1) 0%, transparent 40%),
        radial-gradient(circle at 90% 80%, rgba(124, 58, 237, 0.1) 0%, transparent 40%);
    pointer-events: none;
}

.history-content {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}

.history-phase {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: 32px;
    transition: all 0.3s ease;
}

.history-phase:hover {
    background: rgba(255, 255, 255, 0.08);
    transform: translateY(-4px);
}

.phase-year {
    display: inline-block;
    padding: 4px 14px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 700;
    margin-bottom: 16px;
}

.history-phase h3 {
    font-size: 1.4rem;
    margin-bottom: 12px;
}

.history-phase p {
    color: rgba(255, 255, 255, 0.75);
    line-height: 1.8;
}

/* Timeline */
.timeline-section {
    background: var(--bg);
}

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

.timeline::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    left: 28px;
    width: 2px;
    background: linear-gradient(to bottom, var(--primary), var(--accent));
}

.timeline-item {
    position: relative;
    padding-left: 80px;
    padding-bottom: 48px;
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-marker {
    position: absolute;
    left: 0;
    top: 0;
    width: 56px;
    height: 56px;
    background: white;
    border: 3px solid var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 1.1rem;
    color: var(--primary);
    box-shadow: 0 0 0 6px rgba(37, 99, 235, 0.1);
    transition: all 0.3s ease;
}

.timeline-item:hover .timeline-marker {
    background: var(--primary);
    color: white;
    transform: scale(1.1);
}

.timeline-content {
    background: var(--bg-alt);
    padding: 28px 32px;
    border-radius: var(--radius);
    border-left: 4px solid var(--primary);
    transition: all 0.3s ease;
}

.timeline-item:hover .timeline-content {
    box-shadow: var(--shadow-lg);
    transform: translateX(4px);
}

.timeline-meta {
    display: flex;
    gap: 12px;
    margin-bottom: 12px;
    flex-wrap: wrap;
}

.timeline-year {
    color: var(--primary);
    font-weight: 700;
    font-size: 0.9rem;
}

.timeline-city {
    color: var(--text-light);
    font-size: 0.9rem;
    font-weight: 500;
}

.timeline-content h3 {
    font-size: 1.4rem;
    margin-bottom: 8px;
}

.timeline-theme {
    color: var(--accent);
    font-weight: 600;
    margin-bottom: 12px;
    font-size: 0.95rem;
}

.timeline-content p:last-child {
    color: var(--text-light);
    line-height: 1.8;
}

/* Features */
.features {
    background: var(--bg-alt);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}

.feature-item {
    background: white;
    padding: 36px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-number {
    display: inline-block;
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary-light);
    line-height: 1;
    margin-bottom: 16px;
}

.feature-item h3 {
    font-size: 1.25rem;
    margin-bottom: 12px;
}

.feature-item p {
    color: var(--text-light);
    line-height: 1.8;
}

/* Footer */
.site-footer {
    background: var(--bg-dark);
    color: white;
    padding: 60px 0 24px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 24px;
    padding-bottom: 32px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    margin-bottom: 24px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 16px;
}

.footer-brand .logo-img {
    height: 44px;
}

.footer-brand strong {
    display: block;
    font-size: 1.1rem;
    margin-bottom: 4px;
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9rem;
}

.footer-links {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 12px;
}

.footer-links h4 {
    color: white;
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.friend-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 12px 24px;
}

.friend-links a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.2s ease;
    white-space: nowrap;
}

.friend-links a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.9rem;
}

.footer-bottom a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
}

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

/* Responsive */
@media (max-width: 992px) {
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-description {
        margin-left: auto;
        margin-right: auto;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-visual {
        width: 100%;
        align-items: center;
    }

    .hero-logo {
        max-width: 240px;
    }

    .hero-stats {
        justify-content: center;
        flex-wrap: wrap;
        width: auto;
    }

    .about-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .nav-list {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        gap: 0;
        padding: 16px 24px;
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow-lg);
        transform: translateY(-150%);
        opacity: 0;
        visibility: hidden;
        transition: all 0.3s ease;
    }

    .nav-list.open {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

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

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

    .nav-list a {
        display: block;
        padding: 14px 0;
    }

    .hero {
        padding: 120px 0 60px;
    }

    .hero h1 {
        font-size: 2.2rem;
    }

    .hero-description {
        font-size: 1rem;
    }

    .stat-number {
        font-size: 2.2rem;
    }

    .section {
        padding: 70px 0;
    }

    .section-header h2 {
        font-size: 1.8rem;
    }

    .about-grid,
    .features-grid {
        grid-template-columns: 1fr;
    }

    .timeline::before {
        left: 20px;
    }

    .timeline-item {
        padding-left: 64px;
    }

    .timeline-marker {
        width: 44px;
        height: 44px;
        font-size: 0.9rem;
    }

    .timeline-content {
        padding: 22px;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }

    .footer-brand {
        flex-direction: column;
    }

    .footer-links {
        align-items: center;
    }

    .friend-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.8rem;
    }

    .hero-stats {
        flex-direction: column;
        width: 100%;
    }

    .stat-item {
        justify-content: center;
    }

    .btn {
        width: 100%;
    }

    .hero-actions {
        width: 100%;
    }
}