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

:root {
    --bg: #0a0a0b;
    --bg-elevated: #141416;
    --bg-surface: #1a1a1e;
    --text: #e8e6e3;
    --text-dim: #7a7a80;
    --text-muted: #4a4a50;
    --accent: #c8ff00;
    --accent-dim: rgba(200, 255, 0, 0.12);
    --border: rgba(255, 255, 255, 0.06);
    --border-hover: rgba(255, 255, 255, 0.12);
    --radius: 12px;
    --radius-lg: 20px;
    --font-body: 'Noto Sans SC', -apple-system, sans-serif;
    --font-mono: 'Space Mono', 'SF Mono', monospace;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: var(--font-body);
    background: var(--bg);
    color: var(--text);
    line-height: 1.65;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

::selection {
    background: var(--accent);
    color: var(--bg);
}

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

/* ============================
   NAVIGATION
   ============================ */
#topnav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: 16px 32px;
    transition: background 0.3s, backdrop-filter 0.3s;
}

#topnav.scrolled {
    background: rgba(10, 10, 11, 0.85);
    backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid var(--border);
}

.nav-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-family: var(--font-mono);
    font-size: 20px;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.dot {
    color: var(--accent);
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-link {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-dim);
    letter-spacing: 0.5px;
    text-transform: uppercase;
    transition: color 0.25s;
}

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

.nav-cta {
    font-size: 13px;
    font-weight: 600;
    color: var(--bg);
    background: var(--accent);
    padding: 8px 20px;
    border-radius: 100px;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    transition: transform 0.2s, box-shadow 0.2s;
}

.nav-cta:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 20px rgba(200, 255, 0, 0.3);
}

/* ============================
   HERO
   ============================ */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: radial-gradient(ellipse 80% 60% at 50% 40%, rgba(200, 255, 0, 0.04), transparent);
}

.hero-grain {
    position: absolute;
    inset: 0;
    opacity: 0.35;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.04'/%3E%3C/svg%3E");
    background-size: 200px;
    pointer-events: none;
}

.hero-content {
    position: relative;
    text-align: center;
    padding: 0 24px;
}

.hero-eyebrow {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 40px;
    opacity: 0;
    animation: fadeUp 0.8s 0.2s forwards;
}

.tag {
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 700;
    background: var(--accent);
    color: var(--bg);
    padding: 4px 10px;
    border-radius: 4px;
    letter-spacing: 0.5px;
}

.tag-line {
    width: 32px;
    height: 1px;
    background: var(--text-muted);
}

.tag-text {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--text-muted);
    letter-spacing: 2px;
}

.hero h1 {
    font-size: clamp(64px, 14vw, 160px);
    font-weight: 900;
    line-height: 0.9;
    letter-spacing: -0.04em;
    margin-bottom: 40px;
}

.hero-line {
    display: block;
    opacity: 0;
}

.hero-line-1 {
    color: var(--text);
    animation: fadeUp 0.7s 0.4s forwards;
}

.hero-line-2 {
    color: var(--accent);
    animation: fadeUp 0.7s 0.55s forwards;
}

.hero-desc {
    font-size: 17px;
    color: var(--text-dim);
    line-height: 1.8;
    margin-bottom: 48px;
    opacity: 0;
    animation: fadeUp 0.7s 0.7s forwards;
}

.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    opacity: 0;
    animation: fadeUp 0.7s 0.85s forwards;
}

.hero-scroll-hint {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    opacity: 0;
    animation: fadeUp 0.7s 1.2s forwards;
}

.hero-scroll-hint span {
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--text-muted);
    letter-spacing: 3px;
}

.scroll-line {
    width: 1px;
    height: 40px;
    background: linear-gradient(to bottom, var(--text-muted), transparent);
    animation: scrollPulse 2s ease-in-out infinite;
}

@keyframes scrollPulse {
    0%, 100% { opacity: 0.3; transform: scaleY(0.6); }
    50% { opacity: 1; transform: scaleY(1); }
}

/* ============================
   BUTTONS
   ============================ */
.btn-main {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 32px;
    background: var(--accent);
    color: var(--bg);
    font-weight: 700;
    font-size: 14px;
    border-radius: 100px;
    letter-spacing: 0.3px;
    transition: transform 0.2s, box-shadow 0.2s;
    border: none;
    cursor: pointer;
}

.btn-main:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 32px rgba(200, 255, 0, 0.25);
}

.btn-ghost {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    background: transparent;
    color: var(--text-dim);
    font-weight: 600;
    font-size: 14px;
    border-radius: 100px;
    border: 1px solid var(--border-hover);
    transition: all 0.25s;
    cursor: pointer;
}

.btn-ghost:hover {
    color: var(--text);
    border-color: var(--text-dim);
    transform: translateY(-2px);
}

/* ============================
   SECTION LABELS
   ============================ */
.section-label {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 64px;
    padding: 0 max(24px, calc((100vw - 1200px) / 2));
}

.label-num {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--accent);
    letter-spacing: 1px;
}

.label-text {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-dim);
    text-transform: uppercase;
    letter-spacing: 3px;
}

/* ============================
   FEATURES
   ============================ */
.features {
    padding: 120px 0 80px;
}

.feat-hero-row {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: grid;
    grid-template-columns: 1.3fr 1fr;
    gap: 24px;
    margin-bottom: 64px;
}

.feat-big {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 56px 48px;
    position: relative;
    overflow: hidden;
    transition: border-color 0.3s;
}

.feat-big:hover {
    border-color: var(--border-hover);
}

.feat-big::after {
    content: '';
    position: absolute;
    top: -120px;
    right: -80px;
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, rgba(200, 255, 0, 0.06), transparent 70%);
    pointer-events: none;
}

.feat-big-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--accent-dim);
    border-radius: 14px;
    font-size: 22px;
    color: var(--accent);
    margin-bottom: 32px;
}

.feat-big h2 {
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}

.feat-big p {
    font-size: 15px;
    color: var(--text-dim);
    line-height: 1.8;
    max-width: 440px;
}

.feat-big-tag {
    position: absolute;
    top: 24px;
    right: 24px;
    font-family: var(--font-mono);
    font-size: 10px;
    font-weight: 700;
    color: var(--accent);
    letter-spacing: 2px;
    opacity: 0.5;
}

.feat-side {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.feat-sm {
    flex: 1;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 36px 32px;
    transition: border-color 0.3s, transform 0.3s;
}

.feat-sm:hover {
    border-color: var(--border-hover);
    transform: translateX(4px);
}

.feat-sm-head {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 14px;
}

.feat-sm-head i {
    font-size: 18px;
    color: var(--accent);
    opacity: 0.7;
}

.feat-sm h3 {
    font-size: 20px;
    font-weight: 700;
}

.feat-sm p {
    font-size: 14px;
    color: var(--text-dim);
    line-height: 1.7;
}

/* Feature strip */
.feat-strip {
    max-width: 1200px;
    margin: 0 auto 80px;
    padding: 0 24px;
    display: flex;
    align-items: stretch;
    gap: 0;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.feat-strip-item {
    flex: 1;
    padding: 32px 28px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    transition: background 0.3s;
}

.feat-strip-item:hover {
    background: rgba(200, 255, 0, 0.03);
}

.feat-strip-item i {
    font-size: 18px;
    color: var(--accent);
    opacity: 0.6;
    margin-bottom: 4px;
}

.feat-strip-item span {
    font-size: 16px;
    font-weight: 700;
}

.feat-strip-item small {
    font-size: 13px;
    color: var(--text-muted);
}

.feat-strip-divider {
    width: 1px;
    background: var(--border);
    align-self: stretch;
}

/* Color system */
.color-system {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.color-title {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-bottom: 24px;
}

.color-bar {
    display: flex;
    gap: 4px;
    height: 64px;
    border-radius: var(--radius);
    overflow: hidden;
}

.color-seg {
    flex: 1;
    position: relative;
    cursor: pointer;
    overflow: hidden;
    transition: flex 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.color-seg:hover {
    flex: 2;
}

.seg-fill {
    position: absolute;
    inset: 0;
    background: var(--c);
    opacity: 0.7;
    transition: opacity 0.3s;
}

.color-seg:hover .seg-fill {
    opacity: 1;
}

.color-seg::after {
    content: attr(data-label);
    position: absolute;
    bottom: 8px;
    left: 12px;
    font-size: 11px;
    font-weight: 700;
    color: var(--bg);
    opacity: 0;
    transition: opacity 0.3s;
    white-space: nowrap;
}

.color-seg:hover::after {
    opacity: 1;
}

/* ============================
   DOWNLOAD
   ============================ */
.download {
    padding: 120px 0;
    margin: 40px 0;
    background: linear-gradient(135deg, var(--bg-surface) 0%, var(--bg-elevated) 100%);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.download-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
}

.dl-label {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--accent);
    letter-spacing: 3px;
    display: block;
    margin-bottom: 20px;
}

.download-left h2 {
    font-size: clamp(36px, 5vw, 56px);
    font-weight: 900;
    line-height: 1.1;
    letter-spacing: -0.03em;
    margin-bottom: 20px;
}

.download-left p {
    font-size: 16px;
    color: var(--text-dim);
    line-height: 1.7;
    max-width: 380px;
}

.dl-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 48px 40px;
    position: relative;
}

.dl-card-badge {
    position: absolute;
    top: -12px;
    left: 32px;
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 700;
    background: var(--accent);
    color: var(--bg);
    padding: 4px 16px;
    border-radius: 6px;
    letter-spacing: 2px;
}

.dl-info {
    display: flex;
    gap: 16px;
    margin-bottom: 32px;
}

.dl-version, .dl-size {
    font-family: var(--font-mono);
    font-size: 13px;
    color: var(--text-muted);
}

.btn-download {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    width: 100%;
    padding: 16px;
    background: var(--accent);
    color: var(--bg);
    font-weight: 700;
    font-size: 15px;
    border-radius: var(--radius);
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn-download:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 32px rgba(200, 255, 0, 0.25);
}

/* ============================
   GUIDE - TIMELINE
   ============================ */
.guide {
    padding: 120px 0 80px;
    max-width: 1200px;
    margin: 0 auto;
}

.timeline {
    padding: 0 24px 0 max(24px, calc((100vw - 1200px) / 2 + 24px));
    position: relative;
    margin-bottom: 48px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: max(52px, calc((100vw - 1200px) / 2 + 52px));
    top: 0;
    bottom: 0;
    width: 1px;
    background: var(--border);
}

.tl-item {
    display: flex;
    align-items: flex-start;
    gap: 32px;
    padding: 24px 0;
    opacity: 0;
    transform: translateX(-16px);
    transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.tl-item.visible {
    opacity: 1;
    transform: translateX(0);
}

.tl-marker {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-mono);
    font-size: 14px;
    font-weight: 700;
    color: var(--accent);
    background: var(--bg);
    border: 1px solid var(--accent-dim);
    border-radius: 50%;
    position: relative;
    z-index: 1;
    transition: all 0.3s;
}

.tl-item:hover .tl-marker {
    background: var(--accent);
    color: var(--bg);
    border-color: var(--accent);
}

.tl-content h4 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 4px;
}

.tl-content p {
    font-size: 14px;
    color: var(--text-dim);
}

.guide-links {
    display: flex;
    gap: 16px;
    padding: 0 24px;
    flex-wrap: wrap;
    margin-bottom: 80px;
}

/* Hotkeys */
.hotkeys {
    padding: 0 24px;
}

.hotkeys h3 {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-bottom: 24px;
}

.hk-list {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.hk-item {
    display: flex;
    align-items: center;
    gap: 16px;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 24px;
    transition: border-color 0.3s;
}

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

kbd {
    font-family: var(--font-mono);
    font-size: 13px;
    font-weight: 700;
    color: var(--accent);
    background: var(--accent-dim);
    padding: 6px 12px;
    border-radius: 6px;
    white-space: nowrap;
}

.hk-item span {
    font-size: 14px;
    color: var(--text-dim);
}

/* ============================
   FAQ
   ============================ */
.faq {
    padding: 80px 0 120px;
    max-width: 1200px;
    margin: 0 auto;
}

.faq-list {
    max-width: 720px;
    padding: 0 24px;
}

.faq-item {
    border-bottom: 1px solid var(--border);
}

.faq-item:first-child {
    border-top: 1px solid var(--border);
}

.faq-q {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 24px 0;
    background: none;
    border: none;
    color: var(--text);
    font-family: var(--font-body);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    text-align: left;
    transition: color 0.2s;
}

.faq-q:hover {
    color: var(--accent);
}

.faq-toggle {
    font-family: var(--font-mono);
    font-size: 20px;
    color: var(--text-muted);
    transition: transform 0.3s, color 0.3s;
    flex-shrink: 0;
    width: 28px;
    text-align: center;
}

.faq-item.active .faq-toggle {
    transform: rotate(45deg);
    color: var(--accent);
}

.faq-a {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease, padding 0.35s ease;
}

.faq-item.active .faq-a {
    max-height: 200px;
    padding-bottom: 24px;
}

.faq-a p {
    font-size: 15px;
    color: var(--text-dim);
    line-height: 1.8;
}

/* ============================
   FOOTER
   ============================ */
footer {
    border-top: 1px solid var(--border);
    padding: 40px 24px;
}

.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-logo {
    font-family: var(--font-mono);
    font-size: 18px;
    font-weight: 700;
}

.footer-copy {
    font-size: 12px;
    color: var(--text-muted);
    font-family: var(--font-mono);
    letter-spacing: 1px;
}

/* ============================
   ANIMATIONS
   ============================ */
@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(24px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Scroll-triggered fade */
.feat-big,
.feat-sm,
.feat-strip,
.color-system,
.dl-card {
    opacity: 0;
    transform: translateY(32px);
    transition: opacity 0.7s cubic-bezier(0.4, 0, 0.2, 1),
                transform 0.7s cubic-bezier(0.4, 0, 0.2, 1);
}

.feat-big.visible,
.feat-sm.visible,
.feat-strip.visible,
.color-system.visible,
.dl-card.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ============================
   RESPONSIVE
   ============================ */
@media (max-width: 900px) {
    .feat-hero-row {
        grid-template-columns: 1fr;
    }

    .feat-side {
        flex-direction: row;
    }

    .download-inner {
        grid-template-columns: 1fr;
        gap: 48px;
    }

    .feat-strip {
        flex-direction: column;
    }

    .feat-strip-divider {
        width: 100%;
        height: 1px;
    }
}

@media (max-width: 640px) {
    .nav-right {
        gap: 16px;
    }

    .nav-link {
        display: none;
    }

    .feat-side {
        flex-direction: column;
    }

    .feat-big {
        padding: 36px 28px;
    }

    .color-bar {
        height: 48px;
    }

    .hk-list {
        flex-direction: column;
    }

    .guide-links {
        flex-direction: column;
    }

    .guide-links .btn-main,
    .guide-links .btn-ghost {
        width: 100%;
        justify-content: center;
    }

    .footer-inner {
        flex-direction: column;
        gap: 12px;
        text-align: center;
    }
}