@import url('https://fonts.googleapis.com/css2?family=Roboto+Flex:opsz,wght@8..144,100..1000&family=Rubik+Mono+One&display=swap');
         
       * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        :root {
            --primary-bg: #000;
            --secondary-bg: #1a1b2e;
            --text-primary: #ffffff;
            --text-secondary: #fff;
            --text-muted: #6b7280;
            --accent-blue: #4f46e5;
            --gradient-sphere: radial-gradient(circle at 30% 40%, #ff6b6b, #4ecdc4, #45b7d1, #96ceb4, #feca57);
            --section-spacing: 8rem;
        }

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

        .container {
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 2rem;
        }

        /* Header */
        header {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 1000;
            padding: 1.5rem 0;
            background: rgba(2, 3, 7, 0.8);
            backdrop-filter: blur(20px);
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
        }

        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            font-size: 1.2rem;
            font-weight: 600;
            text-transform: uppercase;
            letter-spacing: 0.1em;
            border: 2px solid var(--text-primary);
            padding: 0.5rem 1rem;
            color: var(--text-primary);
        }

        .nav-links {
            display: flex;
            gap: 3rem;
            list-style: none;
        }

        .nav-links a {
            color: var(--text-secondary);
            text-decoration: none;
            text-transform: uppercase;
            font-size: 0.9rem;
            font-weight: 500;
            letter-spacing: 0.05em;
            transition: color 0.3s ease;
        }

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

        .cta-nav {
            background: transparent;
            border: 1px solid var(--text-primary);
            color: var(--text-primary);
            padding: 0.7rem 1.5rem;
            text-decoration: none;
            text-transform: uppercase;
            font-size: 0.85rem;
            font-weight: 600;
            letter-spacing: 0.05em;
            transition: all 0.3s ease;
        }

        .cta-nav:hover {
            background: var(--text-primary);
            color: var(--primary-bg);
        }

        /* Hero Section */
        .hero {
            height: 100vh;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            text-align: center;
            position: relative;
            overflow: hidden;
        }

        .hero-sphere {
            position: absolute;
            width: 600px;
            height: 600px;
            border-radius: 50%;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            z-index: 1;
            overflow: hidden;

            /* stack gradient + noise */
            background-image: var(--gradient-sphere), url("img/noise.svg");
            background-repeat: no-repeat, repeat;
            background-size: cover, 160px 300px;   /* smaller second value = finer grain */
            background-position: center, 0 0;
            background-blend-mode: multiply, soft-light; /* try overlay for stronger grain */

            /* run both animations */
            animation:
                float 8s ease-in-out infinite,
                grainShift 1.4s steps(2, end) infinite;
            opacity: 0.8; /* overall sphere opacity */
            }

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

            /* subtle jitter in the grain texture only (2nd background layer) */
            @keyframes grainShift {
            from { background-position: center, 0 0; }
            to   { background-position: center, -140px 90px; }
            }

            /* Accessibility: freeze motion if the user prefers reduced motion */
            @media (prefers-reduced-motion: reduce) {
            .hero-sphere { animation: none; }
            }

        .hero-content {
            position: relative;
            z-index: 10;
            max-width: 900px;
        }

        .hero h1 {
            font-size: clamp(3rem, 8vw, 7rem);
            font-weight: 700;
            margin-bottom: 2rem;
            text-transform: uppercase;
            letter-spacing: -0.00em;
            line-height: 0.9;
        }

        .hero-subtitle {
            font-size: 1.2rem;
            color: var(--text-secondary);
            max-width: 600px;
            margin: 0 auto 3rem;
            font-weight: 300;
        }

        .hero-nav {
            position: absolute;
            top: 15%;
            left: 50%;
            transform: translateX(-50%);
            z-index: 10;
        }

        /* Sections */
        section {
            padding: var(--section-spacing) 0;
            position: relative;
        }

        .section-title {
            font-size: clamp(2.5rem, 5vw, 4rem);
            margin-bottom: 3rem;
            text-align: center;
            font-weight: 200;
            letter-spacing: 0.05em;
        }

        .section-content {
            font-size: 1.1rem;
            color: var(--text-secondary);
            max-width: 800px;
            margin: 0 auto;
            text-align: center;
            line-height: 1.8;
            font-weight: 200;
        }

        /* Challenge Grid */
        .challenge-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
            gap: 3rem;
            margin-top: 5rem;
        }

        .challenge-card {
            background: rgba(3, 4, 6, 0.5);
            backdrop-filter: blur(20px);
            border: 1px solid rgba(255, 255, 255, 0.1);
            padding: 3rem;
            position: relative;
            transition: all 0.4s ease;
        }

        .challenge-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 3px;
            background: linear-gradient(90deg, #ff6b6b, #4ecdc4, #45b7d1);
        }

        .challenge-card:hover {
            transform: translateY(-10px);
            border-color: rgba(255, 255, 255, 0.3);
            background: rgba(26, 26, 32, 0.8);
        }

        .challenge-number {
            font-size: 1rem;
            font-weight: 600;
            text-transform: uppercase;
            letter-spacing: 0.2em;
            color: var(--text-secondary);
            margin-bottom: 1.5rem;
        }

        .challenge-title {
            font-size: 1.5rem;
            font-weight: 600;
            margin-bottom: 1.5rem;
            color: var(--text-primary);
            line-height: 1.3;
        }

        .challenge-description {
            color: var(--text-secondary);
            line-height: 1.7;
        }

        /* Submission Types */
        .submission-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 2rem;
            margin-top: 4rem;
        }

        .submission-card {
            background: rgba(26, 27, 46, 0.3);
            border: 1px solid rgba(255, 255, 255, 0.1);
            padding: 2rem;
            text-align: center;
            transition: all 0.3s ease;
        }

        .submission-card:hover {
            background: rgba(33, 34, 43, 0.6);
            transform: translateY(-5px);
        }

        .submission-card h4 {
            font-size: 1.1rem;
            font-weight: 500;
            text-transform: uppercase;
            letter-spacing: 0.05em;
        }

        /* Timeline */
        .timeline {
            max-width: 1000px;
            margin: 5rem auto;
            position: relative;
        }

        .timeline::before {
            content: '';
            position: absolute;
            left: 50%;
            top: 0;
            bottom: 0;
            width: 2px;
            background: linear-gradient(to bottom, #ff6b6b, #4ecdc4, #45b7d1);
            transform: translateX(-50%);
        }

        .timeline-item {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 4rem;
            position: relative;
        }

        .timeline-item:nth-child(even) {
            flex-direction: row-reverse;
        }

        .timeline-content {
            width: 45%;
            background: rgba(26, 27, 46, 0.5);
            backdrop-filter: blur(20px);
            border: 1px solid rgba(255, 255, 255, 0.1);
            padding: 2.5rem;
        }

        .timeline-marker {
            width: 60px;
            height: 60px;
            background: var(--gradient-sphere);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 1.5rem;
            position: relative;
            z-index: 10;
        }

        .timeline-phase {
            font-size: 0.9rem;
            color: var(--text-secondary);
            text-transform: uppercase;
            letter-spacing: 0.1em;
            margin-bottom: 0.5rem;
        }

        .timeline-title {
            font-size: 1.4rem;
            font-weight: 600;
            margin-bottom: 1rem;
        }

        /* Info Sections */
        .info-section {
            background: rgba(26, 27, 46, 0.3);
            border: 1px solid rgba(255, 255, 255, 0.1);
            padding: 4rem;
            margin: 4rem 0;
            text-align: center;
        }

        /* CTA Section */
        .cta-section {
            text-align: center;
            background: rgba(26, 27, 46, 0.5);
            border: 1px solid rgba(255, 255, 255, 0.2);
            padding: 5rem;
            margin: 5rem 0;
            position: relative;
            overflow: hidden;
        }

        .cta-section::before {
            content: '';
            position: absolute;
            top: -50%;
            left: -50%;
            width: 200%;
            height: 200%;
            background: var(--gradient-sphere);
            opacity: 0.05;
            border-radius: 50%;
            animation: rotate 20s linear infinite;
        }

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

        .cta-button {
            display: inline-block;
            background: transparent;
            border: 2px solid var(--text-primary);
            color: var(--text-primary);
            padding: 1.2rem 3rem;
            text-decoration: none;
            text-transform: uppercase;
            font-size: 1rem;
            font-weight: 600;
            letter-spacing: 0.1em;
            margin-top: 2rem;
            position: relative;
            z-index: 10;
            transition: all 0.3s ease;
        }

        .cta-button:hover {
            background: var(--text-primary);
            color: var(--primary-bg);
            transform: translateY(-2px);
        }

        /* Animations */
        .fade-in {
            opacity: 0;
            transform: translateY(50px);
            transition: all 1s ease;
        }

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

        /* Responsive */
        @media (max-width: 768px) {
            :root {
                --section-spacing: 4rem;
            }

            .container {
                padding: 0 1rem;
            }

            .nav-links {
                display: none;
            }

            .hero-sphere {
                width: 400px;
                height: 400px;
            }

            .challenge-grid {
                grid-template-columns: 1fr;
                gap: 2rem;
            }

            .timeline::before {
                left: 30px;
            }

            .timeline-item {
                flex-direction: column;
                align-items: flex-start;
                padding-left: 80px;
            }

            .timeline-item:nth-child(even) {
                flex-direction: column;
                align-items: flex-start;
            }

            .timeline-marker {
                position: absolute;
                left: 0;
            }

            .timeline-content {
                width: 100%;
            }
        }