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

:root {
    --primary: #00f0ff;
    --primary-dark: #00c4d4;
    --secondary: #7c3aed;
    --accent: #f59e0b;
    --bg-dark: #0a0a0f;
    --bg-darker: #050508;
    --bg-card: rgba(15, 15, 25, 0.8);
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.7);
    --text-muted: rgba(255, 255, 255, 0.5);
    --border: rgba(0, 240, 255, 0.2);
    --glow: rgba(0, 240, 255, 0.5);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
    overflow-x: hidden;
    line-height: 1.6;
}

/* Animated Starfield Background */
.stars, .stars2, .stars3 {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

.stars {
    background: transparent url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100"><circle cx="20" cy="20" r="1" fill="white" opacity="0.8"/><circle cx="80" cy="40" r="0.5" fill="white" opacity="0.6"/><circle cx="40" cy="80" r="1.5" fill="white" opacity="0.9"/><circle cx="60" cy="60" r="0.8" fill="white" opacity="0.7"/></svg>') repeat;
    animation: animateStars 200s linear infinite;
}

.stars2 {
    background: transparent url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="150" height="150"><circle cx="30" cy="30" r="1" fill="%2300f0ff" opacity="0.6"/><circle cx="120" cy="60" r="0.5" fill="%2300f0ff" opacity="0.4"/><circle cx="60" cy="120" r="1.2" fill="%2300f0ff" opacity="0.7"/></svg>') repeat;
    animation: animateStars 150s linear infinite reverse;
}

.stars3 {
    background: transparent url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="200" height="200"><circle cx="50" cy="50" r="0.8" fill="%237c3aed" opacity="0.5"/><circle cx="150" cy="100" r="0.6" fill="%237c3aed" opacity="0.4"/><circle cx="100" cy="150" r="1" fill="%237c3aed" opacity="0.6"/></svg>') repeat;
    animation: animateStars 300s linear infinite;
}

@keyframes animateStars {
    from { transform: translateY(0); }
    to { transform: translateY(-2000px); }
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    padding: 1.5rem 0;
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    align-items: center;
}

.nav-left {
    display: flex;
    align-items: center;
    gap: 3rem;
}

.logo {
    display: flex;
    align-items: baseline;
    gap: 0.5rem;
}

.logo-text {
    font-size: 1.8rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.logo-subtitle {
    font-size: 0.9rem;
    color: var(--text-muted);
    font-weight: 500;
    letter-spacing: 0.2em;
}

.nav-links {
    display: flex;
    gap: 2.5rem;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: all 0.3s ease;
    position: relative;
}

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

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

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

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1400px;
    margin: 0 auto;
    padding: 8rem 2rem 4rem;
    position: relative;
    z-index: 1;
}

.hero-content {
    flex: 1;
    max-width: 700px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: rgba(0, 240, 255, 0.1);
    border: 1px solid var(--border);
    border-radius: 50px;
    font-size: 0.85rem;
    color: var(--primary);
    margin-bottom: 2rem;
    font-weight: 500;
}

.pulse-dot {
    width: 8px;
    height: 8px;
    background: var(--primary);
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
    box-shadow: 0 0 10px var(--primary);
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.2); }
}

.hero-title {
    font-size: clamp(3rem, 8vw, 5.5rem);
    font-weight: 900;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    letter-spacing: -0.03em;
}

.gradient-text {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 50%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: block;
}

.hero-subtitle {
    display: block;
    font-size: 0.6em;
    font-weight: 600;
    color: var(--text-secondary);
    margin-top: 0.5rem;
    letter-spacing: 0.1em;
}

.hero-description {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    line-height: 1.8;
    max-width: 600px;
}

.hero-stats {
    display: flex;
    gap: 3rem;
    margin-top: 3rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-family: 'JetBrains Mono', monospace;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

/* Hero Visual */
.hero-visual {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

.neural-network {
    width: 400px;
    height: 400px;
    position: relative;
}

.node {
    position: absolute;
    width: 20px;
    height: 20px;
    background: var(--primary);
    border-radius: 50%;
    box-shadow: 0 0 20px var(--glow), 0 0 40px var(--glow);
    animation: nodePulse 3s ease-in-out infinite;
}

.node-1 { top: 10%; left: 20%; animation-delay: 0s; }
.node-2 { top: 10%; right: 20%; animation-delay: 0.4s; }
.node-3 { top: 50%; left: 10%; animation-delay: 0.8s; }
.node-4 { top: 50%; right: 10%; animation-delay: 1.2s; }
.node-5 { bottom: 10%; left: 20%; animation-delay: 1.6s; }
.node-6 { bottom: 10%; right: 20%; animation-delay: 2s; }
.node-7 { top: 30%; left: 50%; transform: translateX(-50%); animation-delay: 0.2s; }
.node-8 { bottom: 30%; left: 50%; transform: translateX(-50%); animation-delay: 0.6s; }

@keyframes nodePulse {
    0%, 100% { transform: scale(1); opacity: 1; }
    50% { transform: scale(1.3); opacity: 0.7; }
}

.connections {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
}

.connection {
    stroke: var(--primary);
    stroke-width: 1.5;
    stroke-opacity: 0.3;
    animation: connectionFlow 4s ease-in-out infinite;
}

.connection:nth-child(1) { animation-delay: 0s; }
.connection:nth-child(2) { animation-delay: 0.5s; }
.connection:nth-child(3) { animation-delay: 1s; }
.connection:nth-child(4) { animation-delay: 1.5s; }
.connection:nth-child(5) { animation-delay: 2s; }
.connection:nth-child(6) { animation-delay: 2.5s; }
.connection:nth-child(7) { animation-delay: 3s; }

@keyframes connectionFlow {
    0%, 100% { stroke-opacity: 0.2; }
    50% { stroke-opacity: 0.6; }
}

/* Challenges Hero Section */
.challenges-hero {
    min-height: 60vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 10rem 2rem 4rem;
    position: relative;
    z-index: 1;
    text-align: center;
}

.challenges-hero .hero-badge {
    margin-bottom: 2rem;
}

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

.challenges-hero .hero-description {
    max-width: 800px;
    margin: 0 auto;
}

/* Challenges Section */
.challenges-section {
    padding: 8rem 2rem;
    position: relative;
    z-index: 1;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
}

.section-header {
    text-align: center;
    margin-bottom: 5rem;
}

.section-title {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 800;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
}

.section-number {
    font-size: 0.5em;
    color: var(--primary);
    font-family: 'JetBrains Mono', monospace;
    opacity: 0.6;
}

.section-description {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto;
    line-height: 1.8;
}

.challenges-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 4rem;
}

.challenge-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 2.5rem;
    position: relative;
    overflow: hidden;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
}

.challenge-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(0, 240, 255, 0.1), rgba(124, 58, 237, 0.1));
    opacity: 0;
    transition: opacity 0.4s ease;
}

.challenge-card:hover {
    transform: translateY(-10px);
    border-color: var(--primary);
    box-shadow: 0 20px 60px rgba(0, 240, 255, 0.2);
}

.challenge-card:hover::before {
    opacity: 1;
}

.challenge-card:hover .challenge-icon {
    transform: scale(1.1) rotate(5deg);
    color: var(--primary);
}

.challenge-icon {
    width: 50px;
    height: 50px;
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    transition: all 0.4s ease;
    position: relative;
    z-index: 1;
}

.challenge-number {
    position: absolute;
    top: 2rem;
    right: 2rem;
    font-size: 4rem;
    font-weight: 900;
    color: rgba(0, 240, 255, 0.1);
    font-family: 'JetBrains Mono', monospace;
    line-height: 1;
    z-index: 0;
}

.challenge-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-primary);
    position: relative;
    z-index: 1;
}

.challenge-description {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 1.5rem;
    position: relative;
    z-index: 1;
}

.challenge-tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    position: relative;
    z-index: 1;
}

.tag {
    padding: 0.3rem 0.8rem;
    background: rgba(0, 240, 255, 0.1);
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 0.75rem;
    color: var(--primary);
    font-weight: 500;
}

/* CTA Section */
.cta-section {
    padding: 8rem 2rem;
    position: relative;
    z-index: 1;
}

.cta-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 30px;
    padding: 5rem 3rem;
    position: relative;
    overflow: hidden;
}

.cta-content::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(0, 240, 255, 0.1) 0%, transparent 70%);
    animation: rotate 20s linear infinite;
}

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

.cta-title {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 800;
    margin-bottom: 1.5rem;
    position: relative;
    z-index: 1;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.cta-description {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
    line-height: 1.8;
    position: relative;
    z-index: 1;
}

.cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    position: relative;
    z-index: 1;
}

.btn {
    padding: 1rem 2.5rem;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: 'Inter', sans-serif;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: var(--bg-dark);
    box-shadow: 0 10px 30px rgba(0, 240, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 40px rgba(0, 240, 255, 0.4);
}

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

.btn-secondary:hover {
    background: rgba(0, 240, 255, 0.1);
    transform: translateY(-2px);
}

/* Button as link styling */
a.btn {
    text-decoration: none;
    display: inline-block;
}

/* Footer */
.footer {
    padding: 4rem 2rem 2rem;
    border-top: 1px solid var(--border);
    position: relative;
    z-index: 1;
}

.footer-content {
    max-width: 1400px;
    margin: 0 auto;
    text-align: center;
}

.footer-logo {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.footer-text {
    color: var(--text-muted);
    margin-bottom: 2rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
    margin-bottom: 2rem;
}

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

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

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid var(--border);
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .hero {
        flex-direction: column;
        text-align: center;
        padding: 6rem 2rem 4rem;
    }

    .hero-visual {
        margin-top: 3rem;
    }

    .neural-network {
        width: 300px;
        height: 300px;
    }

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

    .challenges-grid {
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    }
}

@media (max-width: 768px) {
    .nav-links {
        gap: 1.5rem;
    }

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

    .hero-title {
        font-size: 2.5rem;
    }

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

    .hero-stats {
        flex-direction: column;
        gap: 1.5rem;
        align-items: center;
    }

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

    .cta-content {
        padding: 3rem 2rem;
    }

    .section-title {
        flex-direction: column;
        gap: 0.5rem;
    }
}

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

.challenge-card {
    animation: fadeInUp 0.6s ease-out backwards;
}

.challenge-card[data-index="0"] { animation-delay: 0.1s; }
.challenge-card[data-index="1"] { animation-delay: 0.2s; }
.challenge-card[data-index="2"] { animation-delay: 0.3s; }
.challenge-card[data-index="3"] { animation-delay: 0.4s; }
.challenge-card[data-index="4"] { animation-delay: 0.5s; }
.challenge-card[data-index="5"] { animation-delay: 0.6s; }
.challenge-card[data-index="6"] { animation-delay: 0.7s; }