:root {
    --bg: #090909;
    --surface: #111111;
    --surface-2: #161616;
    --surface-3: #1c1c1c;
    --border: rgba(255, 255, 255, 0.08);
    --border-strong: rgba(255, 255, 255, 0.14);
    --text: #f4f4f5;
    --muted: #a1a1aa;
    --muted-2: #71717a;
    --accent: #d4a017;
    --accent-hover: #e8b422;
    --radius: 10px;
    --radius-lg: 14px;
    --max: 1120px;
    --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
}

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

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

.container {
    width: min(100% - 2.5rem, var(--max));
    margin-inline: auto;
}

/* Header */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--border);
    background: rgba(9, 9, 9, 0.88);
    backdrop-filter: blur(14px);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 56px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.625rem;
    font-weight: 600;
    font-size: 0.9375rem;
    letter-spacing: -0.02em;
}

.brand-icon {
    border-radius: 8px;
}

.nav {
    display: flex;
    align-items: center;
    gap: 1.75rem;
}

.nav a {
    font-size: 0.875rem;
    color: var(--muted);
    transition: color 0.2s;
}

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

.nav-cta {
    color: var(--text) !important;
    padding: 0.4rem 0.875rem;
    border: 1px solid var(--border-strong);
    border-radius: 8px;
    transition: border-color 0.2s, background 0.2s;
}

.nav-cta:hover {
    border-color: var(--accent);
    background: rgba(212, 160, 23, 0.08);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 0.875rem;
    font-weight: 500;
    padding: 0.625rem 1.25rem;
    border-radius: 8px;
    border: 1px solid transparent;
    transition: background 0.2s, border-color 0.2s, color 0.2s;
}

.btn-primary {
    background: var(--accent);
    color: #0a0a0a;
}

.btn-primary:hover {
    background: var(--accent-hover);
}

.btn-ghost {
    border-color: var(--border-strong);
    color: var(--muted);
}

.btn-ghost:hover {
    color: var(--text);
    background: var(--surface-2);
}

.btn-lg {
    padding: 0.75rem 1.5rem;
    font-size: 0.9375rem;
    white-space: nowrap;
}

/* Hero */
.hero {
    padding: 4.5rem 0 3rem;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1.15fr;
    gap: 3rem;
    align-items: center;
}

.eyebrow {
    font-size: 0.8125rem;
    font-weight: 500;
    letter-spacing: 0.03em;
    color: var(--muted-2);
    margin-bottom: 1rem;
}

.hero h1 {
    font-size: clamp(2.25rem, 5vw, 3.25rem);
    font-weight: 600;
    line-height: 1.12;
    letter-spacing: -0.03em;
    margin-bottom: 1.25rem;
}

.lead {
    font-size: 1.0625rem;
    color: var(--muted);
    max-width: 30rem;
    line-height: 1.7;
    margin-bottom: 2rem;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.meta {
    font-size: 0.8125rem;
    color: var(--muted-2);
}

.hero-shot {
    margin: 0;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    overflow: hidden;
    background: var(--surface);
    cursor: zoom-in;
    box-shadow: 0 8px 40px rgba(0, 0, 0, 0.45);
}

.hero-shot img {
    width: 100%;
    height: auto;
}

/* Section head */
.section-head {
    margin-bottom: 2.5rem;
}

.section-head--compact {
    margin-bottom: 1.5rem;
}

.section-head h2 {
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: -0.02em;
    margin-bottom: 0.5rem;
}

.section-head p {
    color: var(--muted);
    font-size: 0.9375rem;
}

/* Features */
.features {
    padding: 4rem 0 2rem;
    border-top: 1px solid var(--border);
}

.feature-category {
    margin-bottom: 2.75rem;
}

.feature-category:last-child {
    margin-bottom: 0;
}

.category-label {
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 1rem;
    padding-bottom: 0.625rem;
    border-bottom: 1px solid var(--border);
}

.feature-grid {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.75rem;
}

.feature-card {
    position: relative;
    padding: 1.125rem 1.25rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: border-color 0.2s, background 0.2s, box-shadow 0.2s;
}

.feature-card.active {
    background: linear-gradient(145deg, rgba(212, 160, 23, 0.1) 0%, var(--surface-2) 55%);
    border-color: rgba(212, 160, 23, 0.45);
    box-shadow:
        0 0 0 1px rgba(212, 160, 23, 0.12),
        0 4px 20px rgba(212, 160, 23, 0.08);
}

.feature-card.active::before {
    content: 'Nổi bật';
    position: absolute;
    top: 0.75rem;
    right: 0.75rem;
    font-size: 0.625rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--accent);
    background: rgba(212, 160, 23, 0.14);
    border: 1px solid rgba(212, 160, 23, 0.35);
    padding: 0.2rem 0.45rem;
    border-radius: 4px;
}

.feature-card.active h4 {
    color: #fde68a;
    padding-right: 4.5rem;
}

.feature-card:hover {
    border-color: var(--border-strong);
    background: var(--surface-2);
}

.feature-card.active:hover {
    border-color: rgba(212, 160, 23, 0.6);
    background: linear-gradient(145deg, rgba(212, 160, 23, 0.14) 0%, var(--surface-2) 55%);
}

.feature-card h4 {
    font-size: 0.875rem;
    font-weight: 600;
    letter-spacing: -0.01em;
    margin-bottom: 0.375rem;
    color: var(--text);
}

.feature-card p {
    font-size: 0.8125rem;
    color: var(--muted);
    line-height: 1.6;
}

/* Gallery */
.gallery {
    padding: 3rem 0 4.5rem;
    border-top: 1px solid var(--border);
}

.gallery-track {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}

.gallery-item {
    margin: 0;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    overflow: hidden;
    background: var(--surface);
    cursor: zoom-in;
    transition: border-color 0.2s;
}

.gallery-item:hover {
    border-color: var(--border-strong);
}

.gallery-item img {
    width: 100%;
    aspect-ratio: 16 / 10;
    object-fit: cover;
    object-position: top;
}

.gallery-item figcaption {
    padding: 0.625rem 0.875rem;
    font-size: 0.75rem;
    color: var(--muted-2);
    border-top: 1px solid var(--border);
}

/* Download */
.download {
    padding: 0 0 5rem;
}

.download-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
    padding: 1.75rem 2rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    background: var(--surface);
}

.download-copy {
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.download-logo {
    flex-shrink: 0;
    border-radius: 10px;
}

.download-inner h2 {
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.02em;
    margin-bottom: 0.25rem;
}

.download-inner p {
    font-size: 0.875rem;
    color: var(--muted);
}

/* Footer */
.site-footer {
    border-top: 1px solid var(--border);
    padding: 1.5rem 0;
}

.footer-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
    font-size: 0.8125rem;
    color: var(--muted-2);
}

.brand--footer {
    font-size: 0.875rem;
}

.footer-inner > p a {
    color: var(--muted);
    transition: color 0.2s;
}

.footer-inner > p a:hover {
    color: var(--accent);
}

.footer-links {
    display: flex;
    gap: 1.5rem;
}

.footer-links a {
    color: var(--muted-2);
    transition: color 0.2s;
}

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

/* Lightbox */
.lightbox {
    position: fixed;
    inset: 0;
    z-index: 9999;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s ease, visibility 0.25s ease;
}

.lightbox[hidden] {
    display: none;
}

.lightbox.active {
    opacity: 1;
    visibility: visible;
    display: flex;
}

.lightbox-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.9);
    cursor: pointer;
}

.lightbox-content {
    position: relative;
    z-index: 1;
    max-width: min(95vw, 1200px);
    max-height: 92vh;
    padding: 1rem;
}

.lightbox-image {
    max-width: 100%;
    max-height: 88vh;
    border-radius: var(--radius);
    border: 1px solid var(--border-strong);
    cursor: zoom-out;
}

.lightbox-close {
    position: absolute;
    top: 0;
    right: 0;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--surface-2);
    border: 1px solid var(--border-strong);
    border-radius: 8px;
    color: var(--text);
    cursor: pointer;
    transition: background 0.2s;
}

.lightbox-close:hover {
    background: var(--surface-3);
}

/* Responsive */
@media (max-width: 1024px) {
    .feature-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 900px) {
    .hero-grid {
        grid-template-columns: 1fr;
        gap: 2.5rem;
    }

    .gallery-track {
        grid-template-columns: 1fr;
    }

    .download-inner {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 600px) {
    .hero {
        padding-top: 2.5rem;
    }

    .nav a:not(.nav-cta) {
        display: none;
    }

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

    .footer-inner {
        flex-direction: column;
        align-items: flex-start;
    }

    .download-copy {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        transition-duration: 0.01ms !important;
    }
}