/* ========================================
   Reset & Base Styles
   ======================================== */

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

:root {
    /* Color Palette - Dark & Gradient */
    --bg-primary: #0a0e27;
    --bg-secondary: #1a1d35;
    --bg-card: rgba(26, 29, 53, 0.6);

    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #00d4ff 0%, #667eea 100%);
    --gradient-accent: linear-gradient(90deg, #667eea, #764ba2, #00d4ff);

    --text-primary: #ffffff;
    --text-secondary: #b8bdd8;
    --text-muted: #7881a1;

    --accent-purple: #764ba2;
    --accent-blue: #667eea;
    --accent-cyan: #00d4ff;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;

    /* Typography */
    --font-primary: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", "Microsoft YaHei", sans-serif;
    --font-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, monospace;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.8;
    font-size: 16px;
    overflow-x: hidden;
}

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

/* Language Toggle */
.en-text {
    display: none;
}

body.lang-en .cn-text {
    display: none;
}

body.lang-en .en-text {
    display: block;
}

/* ========================================
   Navigation
   ======================================== */

.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 14, 39, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--spacing-sm);
    padding-bottom: var(--spacing-sm);
}

.nav-brand {
    font-size: 1.2rem;
    font-weight: 600;
    background: var(--gradient-secondary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    transition: color 0.3s ease;
    position: relative;
}

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

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: width 0.3s ease;
}

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

.lang-toggle {
    background: var(--gradient-primary);
    color: white;
    border: none;
    padding: 0.5rem 1.2rem;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 600;
    transition: transform 0.2s ease, box-shadow 0.3s ease;
}

.lang-toggle:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.4);
}

/* ========================================
   Hero Section
   ======================================== */

.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xl) 0;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-primary);
    background-image:
        radial-gradient(circle at 20% 30%, rgba(102, 126, 234, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(118, 75, 162, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 50% 50%, rgba(0, 212, 255, 0.1) 0%, transparent 70%);
}

.hero-bg::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image:
        linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px),
        linear-gradient(0deg, rgba(255,255,255,0.03) 1px, transparent 1px);
    background-size: 60px 60px;
    animation: gridMove 20s linear infinite;
}

@keyframes gridMove {
    0% {
        transform: translate(0, 0);
    }
    100% {
        transform: translate(60px, 60px);
    }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4rem);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    line-height: 1.2;
    background: var(--gradient-secondary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: fadeInUp 0.8s ease-out;
}

.hero-description {
    font-size: clamp(1rem, 2vw, 1.15rem);
    color: var(--text-secondary);
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.hero-description p {
    margin-bottom: 0.5rem;
}

.hero-description .highlight {
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1.2em;
    margin-top: var(--spacing-md);
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ========================================
   Section Styles
   ======================================== */

section {
    padding: var(--spacing-xl) 0;
    position: relative;
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    text-align: center;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-content {
    max-width: 800px;
    margin: 0 auto;
}

.section-text {
    font-size: 1.1rem;
    color: var(--text-secondary);
    line-height: 2;
}

.section-text p {
    margin-bottom: 0.5rem;
}

/* Glass Card Effect */
.glass-card {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 24px;
    padding: var(--spacing-lg);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.glass-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 48px rgba(102, 126, 234, 0.2);
}

/* ========================================
   Mission Section
   ======================================== */

.mission {
    background: linear-gradient(180deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
}

/* ========================================
   What We Do Section
   ======================================== */

.what-we-do {
    background: var(--bg-secondary);
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.card {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    padding: var(--spacing-md);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

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

.card:hover {
    transform: translateY(-8px);
    border-color: rgba(102, 126, 234, 0.3);
    box-shadow: 0 12px 40px rgba(102, 126, 234, 0.2);
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
}

.card h3 {
    font-size: 1.3rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

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

/* ========================================
   Events Section
   ======================================== */

.events {
    background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 50%, var(--bg-secondary) 100%);
    position: relative;
}

/* Upcoming Events */
.upcoming-events {
    margin-bottom: var(--spacing-xl);
}

.event-highlight {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 2px solid transparent;
    border-image: var(--gradient-primary) 1;
    border-radius: 24px;
    padding: var(--spacing-lg);
    position: relative;
    overflow: hidden;
    transition: all 0.4s ease;
}

.event-highlight::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(102, 126, 234, 0.1), transparent);
    transition: left 0.6s ease;
}

.event-highlight:hover::before {
    left: 100%;
}

.event-highlight:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 60px rgba(102, 126, 234, 0.3);
    border-image: var(--gradient-secondary) 1;
}

.event-badge {
    display: inline-block;
    padding: 0.5rem 1.5rem;
    background: var(--gradient-primary);
    color: white;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: var(--spacing-sm);
    animation: pulse-badge 2s ease-in-out infinite;
}

@keyframes pulse-badge {
    0%, 100% {
        box-shadow: 0 0 20px rgba(102, 126, 234, 0.5);
    }
    50% {
        box-shadow: 0 0 30px rgba(102, 126, 234, 0.8);
    }
}

.event-highlight h3 {
    font-size: clamp(1.5rem, 3vw, 2rem);
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.event-description {
    color: var(--text-secondary);
    line-height: 1.9;
    margin-bottom: var(--spacing-md);
}

.event-description p {
    margin-bottom: var(--spacing-sm);
}

.event-description strong {
    color: var(--accent-cyan);
    font-weight: 600;
}

.event-details {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
}

.detail-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--text-primary);
    font-size: 1.05rem;
}

.detail-item .icon {
    font-size: 1.3rem;
}

.event-cta {
    text-align: center;
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-md);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.event-cta p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    font-size: 1.05rem;
}

.cta-btn {
    display: inline-block;
    padding: 1rem 3rem;
    background: var(--gradient-primary);
    color: white;
    text-decoration: none;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    z-index: 1;
}

.cta-btn span {
    position: relative;
    z-index: 2;
}

.cta-btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.5s ease, height 0.5s ease;
    z-index: 1;
}

.cta-btn:hover::before {
    width: 300px;
    height: 300px;
}

.cta-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 40px rgba(102, 126, 234, 0.5);
}

/* Past Events Timeline */
.past-events {
    max-width: 900px;
    margin: 0 auto;
}

.timeline-title {
    text-align: center;
    font-size: 1.8rem;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
    position: relative;
}

.timeline-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background: var(--gradient-primary);
    margin: var(--spacing-sm) auto 0;
    border-radius: 2px;
}

.timeline {
    position: relative;
    padding-left: 50px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 15px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(180deg, var(--accent-purple), var(--accent-blue), var(--accent-cyan));
}

.timeline-item {
    position: relative;
    margin-bottom: var(--spacing-lg);
    display: flex;
    gap: var(--spacing-md);
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -42px;
    top: 8px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--gradient-secondary);
    border: 3px solid var(--bg-primary);
    box-shadow: 0 0 20px rgba(102, 126, 234, 0.6);
    z-index: 2;
}

.timeline-date {
    display: flex;
    flex-direction: column;
    align-items: center;
    min-width: 80px;
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    padding: var(--spacing-sm);
    height: fit-content;
}

.timeline-date .month {
    font-size: 1.2rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.timeline-date .year {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.timeline-content {
    flex: 1;
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 16px;
    padding: var(--spacing-md);
    transition: all 0.3s ease;
}

.timeline-content:hover {
    transform: translateX(10px);
    border-color: rgba(102, 126, 234, 0.3);
    box-shadow: 0 8px 30px rgba(102, 126, 234, 0.2);
}

.timeline-content h4 {
    font-size: 1.2rem;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.timeline-content .location {
    color: var(--text-secondary);
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.timeline-content .location .icon {
    color: var(--accent-cyan);
}

.recap-btn {
    display: inline-block;
    margin-top: var(--spacing-sm);
    padding: 0.6rem 1.5rem;
    background: var(--gradient-primary);
    color: white;
    text-decoration: none;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.recap-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.4);
}

/* ========================================
   Why Us Section
   ======================================== */

.why-us {
    background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}

/* ========================================
   About Helen Section
   ======================================== */

.about-helen {
    background: var(--bg-primary);
    position: relative;
    overflow: hidden;
}

.about-helen::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(118, 75, 162, 0.15) 0%, transparent 70%);
    transform: translate(-50%, -50%);
    pointer-events: none;
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-lg);
    align-items: center;
    max-width: 1000px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.about-photo {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

.about-photo img {
    width: 100%;
    max-width: 320px;
    height: auto;
    border-radius: 20px;
    position: relative;
    z-index: 2;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
    transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.about-photo img:hover {
    transform: translateY(-10px) scale(1.02);
    box-shadow: 0 30px 80px rgba(102, 126, 234, 0.4);
}

.photo-glow {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100%;
    height: 100%;
    max-width: 320px;
    border-radius: 20px;
    background: var(--gradient-primary);
    opacity: 0.3;
    filter: blur(40px);
    z-index: 1;
    animation: pulse 3s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 0.3;
        transform: translate(-50%, -50%) scale(1);
    }
    50% {
        opacity: 0.5;
        transform: translate(-50%, -50%) scale(1.1);
    }
}

.about-text h3 {
    font-size: 2rem;
    margin-bottom: var(--spacing-xs);
    background: var(--gradient-secondary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.about-text .role {
    font-size: 1.1rem;
    color: var(--accent-cyan);
    margin-bottom: var(--spacing-md);
    font-weight: 500;
}

.about-text .bio {
    color: var(--text-secondary);
    line-height: 2;
}

.about-text .bio p {
    margin-bottom: var(--spacing-sm);
    font-size: 1.05rem;
}

.social-links {
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.social-links h4 {
    font-size: 1.3rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.links-grid {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.social-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 0.8rem 1.2rem;
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    color: #ffffff;
    text-decoration: none;
    font-size: 0.95rem;
    transition: all 0.3s ease;
}

.social-link:hover {
    transform: translateY(-3px);
    border-color: rgba(102, 126, 234, 0.5);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.2);
    background: rgba(102, 126, 234, 0.1);
    color: #ffffff;
}

.social-link .icon {
    font-size: 1.2rem;
}

/* ========================================
   Subscribe Section
   ======================================== */

.subscribe {
    background: var(--bg-secondary);
    position: relative;
}

.subscribe-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.subscribe-text {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin: var(--spacing-md) 0;
    line-height: 1.8;
}

.subscribe-text p {
    margin: 0;
}

.subscribe-cta {
    text-align: center;
    margin-top: var(--spacing-lg);
}

/* ========================================
   Join Section
   ======================================== */

.join {
    background: var(--bg-primary);
    position: relative;
    overflow: hidden;
}

.join::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(102, 126, 234, 0.1) 0%, transparent 70%);
    animation: rotate 30s linear infinite;
}

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

.join-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.join-text {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 2;
}

.join-cta {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-top: var(--spacing-md);
}

.contact-links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    align-items: center;
}

.contact-btn {
    display: inline-block;
    padding: 1rem 2rem;
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 50px;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 1rem;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.contact-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    transition: left 0.3s ease;
    z-index: -1;
}

.contact-btn:hover::before {
    left: 0;
}

.contact-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
    border-color: transparent;
}

/* ========================================
   Footer
   ======================================== */

.footer {
    background: var(--bg-secondary);
    padding: var(--spacing-md) 0;
    text-align: center;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* ========================================
   Responsive Design
   ======================================== */

@media (max-width: 768px) {
    .nav-links {
        gap: var(--spacing-sm);
    }

    .nav-links a {
        font-size: 0.85rem;
    }

    .hero {
        min-height: 90vh;
        padding: var(--spacing-lg) 0;
    }

    .cards-grid {
        grid-template-columns: 1fr;
    }

    section {
        padding: var(--spacing-lg) 0;
    }

    .glass-card {
        padding: var(--spacing-md);
    }

    .section-title {
        margin-bottom: var(--spacing-md);
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
        text-align: center;
    }

    .about-photo img {
        max-width: 250px;
    }

    .timeline {
        padding-left: 30px;
    }

    .timeline::before {
        left: 8px;
    }

    .timeline-item {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

    .timeline-item::before {
        left: -25px;
        top: 5px;
    }

    .timeline-date {
        width: fit-content;
    }

    .event-details {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
}

@media (max-width: 480px) {
    .nav-brand {
        font-size: 1rem;
    }

    .nav-links a {
        display: none;
    }

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

    .contact-links {
        width: 100%;
    }

    .contact-btn {
        width: 100%;
        text-align: center;
    }
}

/* ========================================
   Animations & Effects
   ======================================== */

/* Scroll reveal animation */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Gradient animation */
@keyframes gradientShift {
    0% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
    100% {
        background-position: 0% 50%;
    }
}

.gradient-text-animated {
    background: var(--gradient-accent);
    background-size: 200% auto;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradientShift 3s ease infinite;
}