/* ===== DESIGN TOKENS ===== */
:root {
    /* Colors */
    --color-bg: #0a0a0f;
    --color-bg-alt: #111118;
    --color-bg-card: #16161f;
    --color-bg-elevated: #1c1c28;
    --color-surface: rgba(255, 255, 255, 0.03);
    --color-border: rgba(255, 255, 255, 0.08);
    --color-border-hover: rgba(255, 255, 255, 0.15);

    --color-text: #e8e8ed;
    --color-text-secondary: #9898a6;
    --color-text-muted: #5a5a6e;

    --color-accent: #00d4ff;
    --color-accent-alt: #00ff88;
    --color-accent-glow: rgba(0, 212, 255, 0.25);
    --color-accent-gradient: linear-gradient(135deg, #00d4ff 0%, #00ff88 100%);
    --color-accent-gradient-text: linear-gradient(135deg, #00d4ff 0%, #00ff88 50%, #00d4ff 100%);

    --color-danger: #ff4466;

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.75rem;
    --font-size-5xl: 3.5rem;
    --font-size-hero: clamp(2.5rem, 6vw, 4.5rem);

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 0.75rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;
    --space-5xl: 8rem;

    /* Borders */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --radius-full: 9999px;

    /* Transitions */
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
    --transition-fast: 200ms var(--ease-out);
    --transition-base: 400ms var(--ease-out);
    --transition-slow: 600ms var(--ease-out);

    /* Shadows */
    --shadow-glow: 0 0 30px var(--color-accent-glow);
    --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.4);
    --shadow-elevated: 0 8px 48px rgba(0, 0, 0, 0.5);
}

/* ===== RESET & BASE ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: 1.6;
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-accent-alt);
}

ul {
    list-style: none;
}

/* ===== UTILITIES ===== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-xl);
}

.text-gradient {
    background: var(--color-accent-gradient-text);
    background-size: 200% auto;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: shimmer 4s linear infinite;
}

@keyframes shimmer {
    0% { background-position: 0% center; }
    100% { background-position: 200% center; }
}

.center { text-align: center; }

.section-label {
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--color-accent);
    margin-bottom: var(--space-md);
}

.section-title {
    font-size: clamp(1.75rem, 4vw, var(--font-size-4xl));
    font-weight: 800;
    line-height: 1.15;
    margin-bottom: var(--space-lg);
    letter-spacing: -0.02em;
}

.section-desc {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: var(--space-lg);
}

.section {
    padding: var(--space-5xl) 0;
    position: relative;
}

/* ===== SCROLL ANIMATIONS ===== */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Stagger children */
.animate-on-scroll:nth-child(2) { transition-delay: 0.1s; }
.animate-on-scroll:nth-child(3) { transition-delay: 0.2s; }
.animate-on-scroll:nth-child(4) { transition-delay: 0.3s; }

/* ===== BUTTONS ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: 0.85rem 1.75rem;
    border-radius: var(--radius-full);
    font-family: var(--font-family);
    font-size: var(--font-size-sm);
    font-weight: 600;
    letter-spacing: 0.02em;
    cursor: pointer;
    border: none;
    transition: all var(--transition-base);
    text-decoration: none;
    line-height: 1;
}

.btn-primary {
    background: var(--color-accent-gradient);
    color: #0a0a0f;
    box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 50px var(--color-accent-glow);
    color: #0a0a0f;
}

.btn-ghost {
    background: transparent;
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-ghost:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
    background: rgba(0, 212, 255, 0.05);
}

.btn-ghost.active {
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: var(--font-size-xs);
}

/* ===== NAVBAR ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: var(--space-md) 0;
    transition: all var(--transition-base);
    background: transparent;
}

.navbar.scrolled {
    background: rgba(10, 10, 15, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-sm) 0;
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-xl);
}

.nav-logo {
    font-size: var(--font-size-xl);
    font-weight: 800;
    letter-spacing: -0.02em;
    text-decoration: none;
}

.logo-snow { color: var(--color-text); }
.logo-vi { color: var(--color-accent); }

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

.nav-links a {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    font-weight: 500;
    transition: color var(--transition-fast);
}

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

.nav-cta {
    background: var(--color-accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    border-radius: 2px;
    transition: all var(--transition-fast);
}

/* ===== HERO ===== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    z-index: 0;
}

.hero-bg-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transform: scale(1.05);
    animation: heroZoom 20s ease-in-out infinite alternate;
}

@keyframes heroZoom {
    0% { transform: scale(1.05); }
    100% { transform: scale(1.15); }
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background:
        linear-gradient(180deg,
            rgba(10, 10, 15, 0.3) 0%,
            rgba(10, 10, 15, 0.5) 40%,
            rgba(10, 10, 15, 0.75) 70%,
            var(--color-bg) 100%
        );
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    padding: var(--space-5xl) var(--space-xl) var(--space-3xl);
}

.hero-badge {
    display: inline-block;
    padding: 0.4rem 1.2rem;
    border-radius: var(--radius-full);
    background: rgba(0, 212, 255, 0.1);
    border: 1px solid rgba(0, 212, 255, 0.3);
    color: var(--color-accent);
    font-size: var(--font-size-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    margin-bottom: var(--space-xl);
}

.hero-title {
    font-size: var(--font-size-hero);
    font-weight: 900;
    line-height: 1.08;
    letter-spacing: -0.03em;
    margin-bottom: var(--space-xl);
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.6), 0 0 40px rgba(0, 0, 0, 0.4);
}

.hero-subtitle {
    font-size: clamp(1rem, 2vw, var(--font-size-lg));
    color: var(--color-text);
    line-height: 1.7;
    max-width: 600px;
    margin: 0 auto var(--space-2xl);
    text-shadow: 0 2px 12px rgba(0, 0, 0, 0.5);
    opacity: 0.85;
}

.hero-actions {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    flex-wrap: wrap;
}

.hero-scroll-indicator {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1;
}

.scroll-arrow {
    width: 24px;
    height: 24px;
    border-right: 2px solid var(--color-text-muted);
    border-bottom: 2px solid var(--color-text-muted);
    transform: rotate(45deg);
    animation: scrollBounce 2s ease-in-out infinite;
}

@keyframes scrollBounce {
    0%, 100% { transform: rotate(45deg) translateY(0); opacity: 0.4; }
    50% { transform: rotate(45deg) translateY(8px); opacity: 1; }
}

/* ===== PROBLEM SECTION ===== */
.section-problem {
    background: var(--color-bg-alt);
}

.problem-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-4xl);
    align-items: center;
}

.smart-glasses-container {
    position: relative;
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.smart-glasses-img {
    width: 100%;
    border-radius: var(--radius-lg);
    transition: all 1s var(--ease-out);
}

.smart-glasses-container:hover .smart-glasses-img {
    filter: blur(2px) grayscale(0.5);
    opacity: 0.6;
}

.price-tag {
    position: absolute;
    top: var(--space-lg);
    right: var(--space-lg);
    background: rgba(255, 68, 102, 0.9);
    color: white;
    font-weight: 800;
    font-size: var(--font-size-xl);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-sm);
    backdrop-filter: blur(8px);
}

.glasses-fade-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, transparent 50%, rgba(10, 10, 15, 0.6) 100%);
    pointer-events: none;
}

.highlight-text {
    color: var(--color-accent);
    font-weight: 500;
}

/* ===== FEATURES SECTION ===== */
.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-2xl);
    margin-top: var(--space-3xl);
}

.feature-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-2xl);
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--color-accent-gradient);
    opacity: 0;
    transition: opacity var(--transition-base);
    z-index: 0;
}

.feature-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-4px);
    box-shadow: var(--shadow-glow);
}

.feature-card:hover::before {
    opacity: 0.03;
}

.feature-card > * {
    position: relative;
    z-index: 1;
}

.feature-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    background: rgba(0, 212, 255, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--space-lg);
    color: var(--color-accent);
}

.feature-icon svg {
    width: 24px;
    height: 24px;
}

.feature-img-wrapper {
    border-radius: var(--radius-md);
    overflow: hidden;
    margin-bottom: var(--space-lg);
    background: var(--color-bg);
    aspect-ratio: 16 / 10;
}

.feature-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.feature-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-bottom: var(--space-sm);
}

.feature-desc {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: 1.6;
}

/* Notification demo */
.notification-demo {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    padding: var(--space-lg);
    height: 100%;
    justify-content: center;
}

.notif {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-sm) var(--space-md);
    opacity: 0;
    transform: translateX(-20px);
    animation: notifSlide 0.5s var(--ease-out) forwards;
}

.notif-1 { animation-delay: 0.5s; }
.notif-2 { animation-delay: 1.2s; }
.notif-3 { animation-delay: 1.9s; }

@keyframes notifSlide {
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.notif-icon {
    font-size: var(--font-size-lg);
    flex-shrink: 0;
}

.notif-text {
    display: flex;
    flex-direction: column;
    gap: 2px;
    min-width: 0;
}

.notif-title {
    font-size: var(--font-size-xs);
    font-weight: 600;
    color: var(--color-text);
}

.notif-body {
    font-size: var(--font-size-xs);
    color: var(--color-text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* ===== HOW IT WORKS — 3D VIEWER ===== */
.section-how {
    background: var(--color-bg-alt);
}

.model-viewer-wrapper {
    max-width: 900px;
    margin: 0 auto;
}

.model-viewer {
    width: 100%;
    aspect-ratio: 16 / 10;
    border-radius: var(--radius-lg);
    overflow: hidden;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    position: relative;
    cursor: grab;
}

.model-viewer:active {
    cursor: grabbing;
}

.model-viewer canvas {
    display: block;
    width: 100%;
    height: 100%;
}

.model-loading {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--space-md);
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    z-index: 2;
    background: var(--color-bg);
}

.model-loading.hidden {
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.5s ease;
}

.loader-ring {
    width: 40px;
    height: 40px;
    border: 3px solid var(--color-border);
    border-top-color: var(--color-accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.model-controls {
    display: flex;
    gap: var(--space-sm);
    justify-content: center;
    margin-top: var(--space-md);
}

/* ===== WAITLIST SECTION ===== */
.section-waitlist {
    padding: var(--space-5xl) 0 var(--space-4xl);
}

.waitlist-card {
    position: relative;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-4xl) var(--space-2xl);
    max-width: 700px;
    margin: 0 auto;
    overflow: hidden;
}

.waitlist-glow {
    position: absolute;
    top: -50%;
    left: 50%;
    transform: translateX(-50%);
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, var(--color-accent-glow) 0%, transparent 70%);
    pointer-events: none;
    opacity: 0.4;
}

.waitlist-card > *:not(.waitlist-glow) {
    position: relative;
    z-index: 1;
}

.waitlist-form {
    max-width: 460px;
    margin: 0 auto;
}

.form-group {
    display: flex;
    gap: var(--space-sm);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    padding: 5px;
    transition: border-color var(--transition-fast);
}

.form-group:focus-within {
    border-color: var(--color-accent);
    box-shadow: var(--shadow-glow);
}

.form-input {
    flex: 1;
    background: transparent;
    border: none;
    outline: none;
    color: var(--color-text);
    font-family: var(--font-family);
    font-size: var(--font-size-sm);
    padding: 0.75rem 1.25rem;
    min-width: 0;
}

.form-input::placeholder {
    color: var(--color-text-muted);
}

.btn-submit {
    flex-shrink: 0;
    border-radius: var(--radius-full);
    padding: 0.75rem 1.5rem;
}

.form-message {
    text-align: center;
    font-size: var(--font-size-sm);
    margin-top: var(--space-md);
    min-height: 1.5rem;
    transition: all var(--transition-fast);
}

.form-message.success {
    color: var(--color-accent-alt);
}

.form-message.error {
    color: var(--color-danger);
}

.form-privacy {
    text-align: center;
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
    margin-top: var(--space-md);
}

.waitlist-divider {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    margin: var(--space-xl) 0;
}

.waitlist-divider::before,
.waitlist-divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--color-border);
}

.waitlist-divider span {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    white-space: nowrap;
}

.waitlist-follow {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    flex-wrap: wrap;
}

.btn-follow {
    padding: 0.7rem 1.5rem;
    font-size: var(--font-size-sm);
}

.btn-follow:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
    background: rgba(0, 212, 255, 0.05);
    transform: translateY(-2px);
}

/* ===== FOOTER ===== */
.footer {
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
    padding: var(--space-3xl) 0 var(--space-xl);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: var(--space-3xl);
    margin-bottom: var(--space-3xl);
}

.footer-tagline {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    line-height: 1.6;
    margin-top: var(--space-md);
}

.footer-links h4 {
    font-size: var(--font-size-sm);
    font-weight: 600;
    margin-bottom: var(--space-md);
    color: var(--color-text);
}

.footer-links ul {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.footer-links a {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    transition: color var(--transition-fast);
}

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

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

/* ===== RESPONSIVE ===== */
@media (max-width: 900px) {
    .problem-layout {
        grid-template-columns: 1fr;
        gap: var(--space-2xl);
    }

    .problem-visual {
        order: -1;
    }

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

    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--space-2xl);
    }
}

@media (max-width: 640px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        background: rgba(10, 10, 15, 0.95);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        border-bottom: 1px solid var(--color-border);
        padding: var(--space-lg);
        gap: var(--space-md);
    }

    .nav-links.open {
        display: flex;
    }

    .nav-toggle {
        display: flex;
    }

    .hero-content {
        padding: var(--space-4xl) var(--space-md) var(--space-2xl);
    }

    .hero-title {
        font-size: clamp(2rem, 8vw, 3rem);
    }

    .hero-actions {
        flex-direction: column;
        align-items: center;
    }

    .form-group {
        flex-direction: column;
        border-radius: var(--radius-md);
        padding: var(--space-xs);
    }

    .btn-submit {
        width: 100%;
        justify-content: center;
    }

    .section {
        padding: var(--space-3xl) 0;
    }

    .model-viewer {
        aspect-ratio: 4 / 3;
    }

    .model-controls {
        flex-direction: column;
        align-items: center;
    }

    .waitlist-card {
        padding: var(--space-2xl) var(--space-lg);
    }
}