/* ===== DESIGN TOKENS ===== */
:root {
    /* Background */
    --bg-page: #14141c;
    --bg-block: #191921;
    --bg-card: #1c1c26;

    /* Text */
    --text-primary: #ffffff;
    --text-secondary: #7979fc;
    --text-tertiary: rgba(255, 255, 255, 0.5);
    --text-cta: #14141c;

    /* Button */
    --btn-accent: #3636e3;
    --btn-accent-hover: #4444f0;
    --btn-accent-pressed: #1a1a5c;
    --btn-cta: #fafafa;
    --btn-cta-hover: #e0e0e0;
    --btn-cta-pressed: #8c8c8c;

    /* Border */
    --border-primary: rgba(255, 255, 255, 0.06);
    --border-popup: rgba(255, 255, 255, 0.1);

    /* Glow */
    --glow-accent: rgba(54, 54, 227, 0.4);
    --glow-subtle: rgba(121, 121, 252, 0.08);

    /* Spacing */
    --space-xs: 8px;
    --space-sm: 16px;
    --space-md: 24px;
    --space-lg: 40px;
    --space-xl: 64px;
    --space-2xl: 96px;

    /* Layout */
    --max-width: 960px;
    --radius: 8px;
    --radius-lg: 12px;

    /* Font */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    /* Motion */
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --ease-out-soft: cubic-bezier(0.33, 1, 0.68, 1);
    --duration-fast: 150ms;
    --duration-normal: 250ms;
    --duration-slow: 400ms;
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-family);
    background-color: var(--bg-page);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

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

a {
    text-decoration: none;
    color: inherit;
}

/* ===== SCROLL FADE-IN ===== */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity var(--duration-slow) var(--ease-out),
    transform var(--duration-slow) var(--ease-out);
}

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

/* ===== HERO SECTION ===== */
.hero {
    text-align: center;
    padding: var(--space-lg) var(--space-md);
    position: relative;
}

.hero::before {
    content: '';
    position: absolute;
    top: -120px;
    left: 50%;
    transform: translateX(-50%);
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, var(--glow-accent) 0%, transparent 70%);
    opacity: 0.3;
    pointer-events: none;
    z-index: 0;
}

.hero__container {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-sm);
    position: relative;
    z-index: 1;
}

.hero__logo {
    width: 240px;
    height: auto;
    margin-bottom: 32px;
}

.hero__headline {
    font-size: clamp(1.5rem, 4vw, 2rem);
    font-weight: 700;
    line-height: 1.15;
    max-width: 700px;
    letter-spacing: -0.02em;
}

.hero__subtitle {
    font-size: clamp(0.95rem, 2vw, 1.125rem);
    color: var(--text-tertiary);
    max-width: 760px;
    line-height: 1.7;
}

.hero__cta-prompt {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    margin-top: var(--space-xs);
    letter-spacing: 0.01em;
}

/* ===== VERSION CARDS ===== */
.hero__versions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-sm);
    margin-top: 32px;
    width: 100%;
    max-width: var(--max-width);
}

.version-card {
    display: block;
    position: relative;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-popup);
    background: var(--bg-block);
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
    overflow: hidden;
    cursor: pointer;
    transition: border-color var(--duration-normal) var(--ease-out),
    box-shadow var(--duration-normal) var(--ease-out),
    margin var(--duration-normal) var(--ease-out),
    transform var(--duration-normal) var(--ease-out);
}

.version-card:active {
    transform: scale(0.98);
}

.version-card:focus-visible {
    outline: 2px solid var(--text-secondary);
    outline-offset: 3px;
}

.version-card__preview {
    position: relative;
    overflow: hidden;
    background: var(--bg-block);
    margin-bottom: -1px;
}

.version-card__preview img {
    width: 100%;
    aspect-ratio: 16 / 9;
    object-fit: cover;
    display: block;
    transition: transform var(--duration-slow) var(--ease-out-soft);
}

.version-card:hover .version-card__preview img {
    transform: scale(1.04);
}

.version-card__preview::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 60%;
    background: linear-gradient(to top, var(--bg-block) 0%, transparent 100%);
    pointer-events: none;
}

.version-card__info {
    padding: var(--space-sm) var(--space-md);
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.version-card__label {
    flex: 1;
}

.version-card__title {
    font-size: 1rem;
    font-weight: 600;
    letter-spacing: -0.01em;
    color: var(--text-primary);
}

.version-card__sub {
    font-size: 0.8rem;
    color: var(--text-tertiary);
    margin-top: 2px;
}

.version-card__pill {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 16px;
    border-radius: 999px;
    font-size: 0.825rem;
    font-weight: 600;
    letter-spacing: 0.01em;
    color: var(--text-primary);
    flex-shrink: 0;
    white-space: nowrap;
    transition: background-color var(--duration-normal) var(--ease-out),
    box-shadow var(--duration-normal) var(--ease-out),
    transform var(--duration-normal) var(--ease-out);
}

.version-card--3d .version-card__pill {
    background: var(--btn-accent);
    box-shadow: 0 0 0 1px rgba(121, 121, 252, 0.4),
    0 6px 20px rgba(54, 54, 227, 0.35);
}

.version-card--2d .version-card__pill {
    background: rgba(255, 255, 255, 0.12);
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.15);
}

.version-card__pill svg {
    width: 14px;
    height: 14px;
    color: var(--text-primary);
    transition: transform var(--duration-normal) var(--ease-out);
}

.version-card:hover .version-card__pill svg {
    transform: translateX(3px);
}

.version-card--3d:hover .version-card__pill {
    background: var(--btn-accent-hover);
}

.version-card--2d:hover .version-card__pill {
    background: rgba(255, 255, 255, 0.2);
}

/* Version card hover: glow border + gradient overlay */
.version-card::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: var(--radius-lg);
    opacity: 0;
    z-index: 1;
    pointer-events: none;
    transition: opacity var(--duration-normal) var(--ease-out);
}

.version-card--3d::before {
    background: linear-gradient(to top, rgba(54, 54, 227, 0.25) 0%, transparent 60%);
}

.version-card--2d::before {
    background: linear-gradient(to top, rgba(255, 255, 255, 0.1) 0%, transparent 60%);
}

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

.version-card--3d:hover {
    border-color: rgba(121, 121, 252, 0.4);
    box-shadow: 0 0 20px rgba(121, 121, 252, 0.15),
    0 4px 24px rgba(0, 0, 0, 0.3);
    /*transform: translateY(-2px);*/
    margin-top: -4px;
    margin-bottom: 4px;
}

.version-card--2d:hover {
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 0 20px rgba(255, 255, 255, 0.06),
    0 4px 24px rgba(0, 0, 0, 0.3);
    transform: translateY(-2px);
}

/* ===== FEATURES SECTION ===== */
.features {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--space-xl) var(--space-md);
}

.features__heading {
    color: var(--text-primary);
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    font-weight: 600;
    text-align: center;
    margin-bottom: var(--space-lg);
    letter-spacing: -0.01em;
}

.features__heading-accent {
    color: #4AB4E9;
}

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

.feature-card {
    display: grid;
    grid-template-columns: 2fr 3fr;
    background: var(--bg-block);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: border-color var(--duration-normal) var(--ease-out),
    box-shadow var(--duration-normal) var(--ease-out),
    background-color var(--duration-normal) var(--ease-out);
}

.feature-card__image {
    padding: var(--space-md);
    display: flex;
    align-items: center;
    justify-content: center;
}

.feature-card__image img {
    width: 100%;
    max-width: 400px;
    border-radius: var(--radius);
    aspect-ratio: 16 / 9;
    object-fit: cover;
    transition: transform var(--duration-slow) var(--ease-out-soft);
}

.feature-card__content {
    padding: var(--space-md) var(--space-lg);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.feature-card__content h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--space-xs);
    color: var(--text-secondary);
    letter-spacing: -0.01em;
}

.feature-card__content p {
    font-size: 0.925rem;
    color: var(--text-tertiary);
    line-height: 1.7;
}

/* ===== FOOTER ===== */
.footer {
    padding: var(--space-lg) var(--space-md);
    text-align: center;
    border-top: 1px solid var(--border-primary);
}

.footer__nav {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--space-sm);
}

.footer__nav a {
    color: var(--text-tertiary);
    font-size: 0.85rem;
    letter-spacing: 0.01em;
    transition: color var(--duration-normal) var(--ease-out);
}

.footer__nav a:hover {
    color: var(--text-secondary);
}

.footer__nav a:focus-visible {
    outline: 2px solid var(--text-secondary);
    outline-offset: 3px;
    border-radius: 2px;
}

.footer__nav span {
    color: rgba(255, 255, 255, 0.15);
    user-select: none;
}

/* ===== RESPONSIVE: MOBILE ===== */
@media (max-width: 767px) {
    .hero {
        padding: var(--space-lg) var(--space-sm);
    }

    .hero::before {
        width: 360px;
        height: 360px;
        top: -60px;
    }

    .hero__logo {
        width: 180px;
    }

    .hero__versions {
        grid-template-columns: 1fr;
        max-width: 420px;
        margin-left: auto;
        margin-right: auto;
    }

    .feature-card {
        grid-template-columns: 1fr;
    }

    .feature-card__content {
        padding: var(--space-sm) var(--space-md);
        text-align: center;
    }

    .features {
        padding: var(--space-lg) var(--space-sm);
    }
}

/* ===== RESPONSIVE: LARGE DESKTOP ===== */
@media (min-width: 1024px) {
    .hero {
        padding: var(--space-lg) var(--space-md);
    }

    .hero::before {
        width: 800px;
        height: 800px;
        top: -200px;
    }

    .features {
        padding: var(--space-lg) var(--space-md);
    }
}

/* ===== REDUCED MOTION ===== */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }

    html {
        scroll-behavior: auto;
    }

    .fade-in {
        opacity: 1;
        transform: none;
    }
}