/* ============================================================
   ii — inference engine · landing page styles
   Dark, neural-themed design system
   ============================================================ */

:root {
    --bg:        #070a12;
    --bg-2:      #0b1020;
    --surface:   #0e1424;
    --surface-2: #131b30;
    --border:    rgba(148, 163, 184, 0.12);
    --border-2:  rgba(148, 163, 184, 0.22);

    --text:   #e7ecf5;
    --text-2: #9aa6bd;
    --text-3: #6b7689;

    --c1: #2DE2C8;   /* teal   */
    --c2: #6366F1;   /* indigo */
    --c3: #A855F7;   /* purple */
    --grad: linear-gradient(120deg, var(--c1), var(--c2) 55%, var(--c3));

    --radius: 16px;
    --radius-sm: 10px;
    --maxw: 1180px;
    --shadow: 0 24px 60px -28px rgba(0, 0, 0, 0.85);
    --shadow-glow: 0 0 0 1px var(--border), 0 24px 60px -30px rgba(99, 102, 241, 0.45);

    --mono: 'JetBrains Mono', ui-monospace, 'SFMono-Regular', Consolas, monospace;
    --sans: 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
}

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

html { scroll-behavior: smooth; scroll-padding-top: 90px; }

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

/* subtle ambient gradient wash on the whole page */
body::before {
    content: "";
    position: fixed;
    inset: 0;
    background:
        radial-gradient(60% 50% at 80% -5%, rgba(99, 102, 241, 0.18), transparent 60%),
        radial-gradient(50% 45% at 10% 5%, rgba(45, 226, 200, 0.10), transparent 60%);
    pointer-events: none;
    z-index: 0;
}

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; position: relative; z-index: 1; }

a { color: inherit; text-decoration: none; transition: color .2s ease; }
code { font-family: var(--mono); font-size: 0.9em; }

.gradient-text {
    background: var(--grad);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

/* ---------------- Navbar ---------------- */
.navbar {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    padding: 14px 0;
    transition: background .3s ease, border-color .3s ease, padding .3s ease;
    border-bottom: 1px solid transparent;
}
.navbar.scrolled {
    background: rgba(8, 11, 19, 0.78);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom-color: var(--border);
    padding: 9px 0;
}
.nav-container { display: flex; align-items: center; justify-content: space-between; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.nav-logo { display: flex; align-items: baseline; gap: 8px; }
.nav-logo .logo-img { width: 34px; height: 34px; align-self: center; }
.logo-text { font-size: 1.4rem; font-weight: 800; letter-spacing: -0.02em; }
.logo-sub { font-size: 0.78rem; color: var(--text-3); font-weight: 500; }
.nav-menu { display: flex; align-items: center; gap: 6px; list-style: none; }
.nav-link {
    padding: 8px 14px; border-radius: 999px; font-size: 0.94rem; font-weight: 500;
    color: var(--text-2); transition: color .2s, background .2s;
}
.nav-link:hover { color: var(--text); background: rgba(148, 163, 184, 0.08); }
.github-link {
    background: rgba(148, 163, 184, 0.07);
    border: 1px solid var(--border-2);
    color: var(--text);
}
.github-link:hover { border-color: var(--c2); background: rgba(99, 102, 241, 0.14); }

.hamburger { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 6px; }
.hamburger .bar { width: 24px; height: 2px; background: var(--text); border-radius: 2px; transition: transform .3s, opacity .3s; }
.hamburger.open .bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open .bar:nth-child(2) { opacity: 0; }
.hamburger.open .bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------------- Hero ---------------- */
.hero {
    position: relative;
    padding: 170px 0 90px;
    text-align: center;
    overflow: hidden;
}
.hero-canvas { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 0; opacity: 0.55; }
.hero-glow {
    position: absolute; top: -10%; left: 50%; transform: translateX(-50%);
    width: 900px; height: 520px;
    background: radial-gradient(closest-side, rgba(99, 102, 241, 0.22), transparent);
    filter: blur(20px); pointer-events: none; z-index: 0;
}
.hero-content { position: relative; z-index: 2; max-width: 880px; margin: 0 auto; padding: 0 24px; }

.hero-badge {
    display: inline-flex; align-items: center; gap: 9px;
    padding: 7px 16px; margin-bottom: 28px;
    border: 1px solid var(--border-2); border-radius: 999px;
    background: rgba(14, 20, 36, 0.6); backdrop-filter: blur(6px);
    font-size: 0.86rem; color: var(--text-2); font-weight: 500;
}
.hero-badge .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--c1); box-shadow: 0 0 12px var(--c1); }

.hero-title {
    font-size: clamp(2.4rem, 6vw, 4.4rem);
    line-height: 1.05; font-weight: 800; letter-spacing: -0.03em;
    margin-bottom: 22px;
}
.hero-description { font-size: clamp(1rem, 1.6vw, 1.2rem); color: var(--text-2); max-width: 720px; margin: 0 auto 34px; }
.hero-description strong { color: var(--text); }

.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.hero-actions.center { justify-content: center; }

.btn {
    display: inline-flex; align-items: center; gap: 9px;
    padding: 13px 24px; border-radius: 999px;
    font-size: 0.98rem; font-weight: 600; cursor: pointer;
    transition: transform .2s ease, box-shadow .2s ease, background .2s ease, border-color .2s;
    border: 1px solid transparent;
}
.btn-primary { background: var(--grad); color: #0a0e16; box-shadow: 0 12px 30px -10px rgba(99, 102, 241, 0.6); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 18px 40px -12px rgba(99, 102, 241, 0.7); }
.btn-ghost { background: rgba(148, 163, 184, 0.06); border-color: var(--border-2); color: var(--text); }
.btn-ghost:hover { transform: translateY(-2px); border-color: var(--c2); background: rgba(99, 102, 241, 0.12); }

/* hero code card */
.hero-code {
    margin: 46px auto 0; max-width: 680px; text-align: left;
    background: var(--surface); border: 1px solid var(--border);
    border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden;
}
.code-head {
    display: flex; align-items: center; gap: 10px;
    padding: 10px 14px; border-bottom: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.015);
}
.code-head .dots { display: flex; gap: 6px; }
.code-head .dots i { width: 11px; height: 11px; border-radius: 50%; background: #2a3550; display: block; }
.code-file { font-size: 0.8rem; color: var(--text-3); font-family: var(--mono); }
.copy-btn {
    margin-left: auto; background: none; border: 0; color: var(--text-3);
    cursor: pointer; font-size: 0.9rem; padding: 5px 8px; border-radius: 6px; transition: color .2s, background .2s;
}
.copy-btn:hover { color: var(--text); background: rgba(148, 163, 184, 0.1); }
.copy-btn.copied { color: var(--c1); }

pre { padding: 18px 18px; overflow-x: auto; }
pre code { font-size: 0.86rem; line-height: 1.7; color: #cdd6e6; white-space: pre; }
.c-cmt { color: #5d6b86; font-style: italic; }
.c-prompt { color: var(--c1); user-select: none; }
.c-kw { color: #8aa2ff; }
.c-str { color: #6ee7b7; }
.c-num { color: #fca5a5; }
.c-pre { color: var(--c3); }

/* ---------------- Highlights ---------------- */
.highlights { padding: 8px 0 10px; }
.highlights-grid {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px;
    background: var(--surface); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 30px 24px;
}
.hl { text-align: center; }
.hl-num { font-size: clamp(1.6rem, 3vw, 2.4rem); font-weight: 800; letter-spacing: -0.02em; line-height: 1.1; }
.hl-label { font-size: 0.88rem; color: var(--text-2); margin-top: 4px; }

/* ---------------- Sections ---------------- */
.section { padding: 96px 0; position: relative; }
.section-alt { background: linear-gradient(180deg, transparent, rgba(14, 20, 36, 0.5), transparent); }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 56px; }
.eyebrow {
    display: inline-block; font-size: 0.8rem; font-weight: 600; letter-spacing: 0.14em; text-transform: uppercase;
    color: var(--c1); margin-bottom: 14px;
}
.section-title { font-size: clamp(1.7rem, 3.4vw, 2.6rem); font-weight: 800; letter-spacing: -0.025em; line-height: 1.15; }
.section-sub { color: var(--text-2); font-size: 1.05rem; margin-top: 16px; }

/* feature grid */
.feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.card {
    background: var(--surface); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 26px 22px;
    transition: transform .25s ease, border-color .25s ease, box-shadow .25s ease;
    position: relative; overflow: hidden;
}
.card::after {
    content: ""; position: absolute; inset: 0;
    background: linear-gradient(160deg, rgba(99, 102, 241, 0.07), transparent 45%);
    opacity: 0; transition: opacity .25s ease;
}
.card:hover { transform: translateY(-4px); border-color: var(--border-2); box-shadow: var(--shadow-glow); }
.card:hover::after { opacity: 1; }
.card-icon {
    width: 46px; height: 46px; border-radius: 12px;
    display: grid; place-items: center; margin-bottom: 16px; font-size: 1.15rem;
    background: rgba(99, 102, 241, 0.12); color: var(--c1);
    border: 1px solid var(--border-2);
}
.card h3 { font-size: 1.08rem; font-weight: 700; margin-bottom: 8px; letter-spacing: -0.01em; }
.card p { font-size: 0.93rem; color: var(--text-2); }
.card code { color: #a9b6ff; background: rgba(99, 102, 241, 0.1); padding: 1px 6px; border-radius: 5px; }

/* backend grid */
.backend-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; max-width: 920px; margin: 0 auto; }
.backend-card {
    background: var(--surface); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 26px 24px;
    transition: transform .25s, border-color .25s, box-shadow .25s;
}
.backend-card:hover { transform: translateY(-3px); border-color: var(--border-2); box-shadow: var(--shadow-glow); }
.backend-card.featured { border-color: rgba(99, 102, 241, 0.4); background: linear-gradient(160deg, rgba(99, 102, 241, 0.08), var(--surface)); }
.backend-top { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 12px; }
.backend-name { font-size: 1.15rem; font-weight: 700; }
.backend-name .tag { font-size: 0.68rem; font-weight: 600; color: var(--c1); border: 1px solid var(--border-2); padding: 2px 7px; border-radius: 6px; vertical-align: middle; margin-left: 4px; }
.badge-on { font-size: 0.72rem; font-weight: 700; color: #0a0e16; background: var(--grad); padding: 4px 10px; border-radius: 999px; }
.badge-off { font-size: 0.72rem; font-weight: 600; color: var(--text-3); border: 1px solid var(--border-2); padding: 3px 10px; border-radius: 999px; }
.backend-desc { font-size: 0.94rem; color: var(--text-2); margin-bottom: 16px; }
.backend-desc strong { color: var(--text); }
.backend-meta { list-style: none; display: flex; flex-wrap: wrap; gap: 8px 18px; font-size: 0.85rem; color: var(--text-2); }
.backend-meta i { color: var(--c1); margin-right: 6px; width: 14px; }
.backend-meta code { color: #a9b6ff; }

/* engine / library split */
.engine-wrap { display: grid; grid-template-columns: 1.05fr 1fr; gap: 48px; align-items: center; }
.engine-wrap.reverse .engine-text { order: 2; }
.engine-text .section-title { font-size: clamp(1.5rem, 2.8vw, 2.1rem); }
.engine-text .eyebrow { display: block; text-align: left; }
.check-list { list-style: none; margin-top: 26px; display: grid; gap: 14px; }
.check-list li { display: flex; gap: 12px; font-size: 0.96rem; color: var(--text-2); align-items: flex-start; }
.check-list strong { color: var(--text); }
.check-list i {
    margin-top: 3px; color: var(--c1); font-size: 0.8rem; flex-shrink: 0;
    width: 22px; height: 22px; border-radius: 50%; display: grid; place-items: center;
    background: rgba(45, 226, 200, 0.12); border: 1px solid var(--border-2);
}
.engine-code {
    background: var(--surface); border: 1px solid var(--border);
    border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden;
}

/* tabs */
.tabs { max-width: 880px; margin: 0 auto; }
.tab-bar { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 18px; justify-content: center; }
.tab {
    padding: 9px 18px; border-radius: 999px; border: 1px solid var(--border-2);
    background: rgba(148, 163, 184, 0.05); color: var(--text-2);
    font-family: var(--sans); font-size: 0.9rem; font-weight: 600; cursor: pointer;
    transition: all .2s;
}
.tab:hover { color: var(--text); }
.tab.active { color: #0a0e16; background: var(--grad); border-color: transparent; }
.tab-panel { display: none; }
.tab-panel.active { display: block; animation: fade .3s ease; }
@keyframes fade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
.code-block {
    position: relative; background: var(--surface);
    border: 1px solid var(--border); border-radius: var(--radius);
    box-shadow: var(--shadow); overflow: hidden;
}
.code-block .copy-btn { position: absolute; top: 10px; right: 10px; z-index: 2; }
.code-block pre { padding-top: 20px; }

/* downloads */
.dl-version {
    display: inline-block; margin-left: 6px; padding: 2px 10px; border-radius: 999px;
    font-family: var(--mono); font-size: 0.82rem; font-weight: 600; color: var(--c1);
    background: rgba(45, 226, 200, 0.1); border: 1px solid var(--border-2); vertical-align: middle;
}
.download-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; max-width: 920px; margin: 0 auto; }
.download-card {
    display: flex; align-items: center; gap: 16px;
    background: var(--surface); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 22px 22px;
    transition: transform .25s, border-color .25s, box-shadow .25s;
}
.download-card:hover { transform: translateY(-4px); border-color: var(--border-2); box-shadow: var(--shadow-glow); }
.download-card.disabled { opacity: 0.6; pointer-events: none; }
.dl-icon {
    width: 52px; height: 52px; flex-shrink: 0; border-radius: 14px;
    display: grid; place-items: center; font-size: 1.6rem; color: var(--text);
    background: rgba(99, 102, 241, 0.12); border: 1px solid var(--border-2);
}
.dl-body { flex: 1; min-width: 0; }
.dl-body h3 { font-size: 1.1rem; font-weight: 700; letter-spacing: -0.01em; }
.dl-meta { font-size: 0.82rem; color: var(--text-3); font-family: var(--mono); }
.dl-cta {
    width: 40px; height: 40px; flex-shrink: 0; border-radius: 50%;
    display: grid; place-items: center; color: var(--c1);
    background: rgba(45, 226, 200, 0.1); border: 1px solid var(--border-2);
    transition: background .25s, color .25s, transform .25s;
}
.download-card:hover .dl-cta { background: var(--grad); color: #0a0e16; transform: scale(1.08); }
.download-foot { text-align: center; margin-top: 28px; color: var(--text-3); font-size: 0.92rem; }
.download-foot a { color: var(--text-2); }
.download-foot a:hover { color: var(--c1); }
.download-foot i { color: var(--c1); margin-right: 6px; }
.download-foot .sep { margin: 0 14px; opacity: 0.5; }

@media (max-width: 720px) {
    .download-grid { grid-template-columns: 1fr; }
    .download-foot .sep { display: block; height: 8px; margin: 0; }
}

/* CTA */
.cta { padding: 90px 0; text-align: center; }
.cta-inner {
    background: linear-gradient(160deg, rgba(99, 102, 241, 0.14), rgba(45, 226, 200, 0.06));
    border: 1px solid var(--border-2); border-radius: 24px;
    padding: 64px 32px; position: relative; overflow: hidden;
}
.cta-inner::before {
    content: ""; position: absolute; top: -50%; left: 50%; transform: translateX(-50%);
    width: 600px; height: 400px; background: radial-gradient(closest-side, rgba(99, 102, 241, 0.25), transparent);
    filter: blur(10px);
}
.cta-inner h2 { font-size: clamp(1.6rem, 3.2vw, 2.4rem); font-weight: 800; letter-spacing: -0.025em; position: relative; }
.cta-inner p { color: var(--text-2); margin: 14px auto 30px; max-width: 540px; position: relative; }
.cta-inner .hero-actions { position: relative; }

/* footer */
.footer { border-top: 1px solid var(--border); padding: 60px 0 30px; background: rgba(8, 11, 19, 0.5); }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr; gap: 40px; }
.footer-brand p { color: var(--text-2); font-size: 0.92rem; margin-top: 14px; max-width: 340px; }
.footer-col h4 { font-size: 0.82rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--text-3); margin-bottom: 16px; }
.footer-col a { display: block; color: var(--text-2); font-size: 0.94rem; padding: 5px 0; }
.footer-col a:hover { color: var(--c1); }
.footer-bottom {
    display: flex; align-items: center; justify-content: space-between;
    margin-top: 44px; padding-top: 22px; border-top: 1px solid var(--border);
    color: var(--text-3); font-size: 0.88rem;
}
.footer-bottom a { font-size: 1.2rem; color: var(--text-3); }
.footer-bottom a:hover { color: var(--c1); }

/* reveal on scroll */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ---------------- Responsive ---------------- */
@media (max-width: 980px) {
    .feature-grid { grid-template-columns: repeat(2, 1fr); }
    .engine-wrap { grid-template-columns: 1fr; gap: 32px; }
    .engine-wrap.reverse .engine-text { order: 0; }
}
@media (max-width: 820px) {
    .nav-menu {
        position: fixed; top: 62px; right: 0; width: min(80vw, 300px);
        height: calc(100vh - 62px); flex-direction: column; align-items: flex-start;
        gap: 6px; padding: 24px; background: rgba(8, 11, 19, 0.97);
        backdrop-filter: blur(14px); border-left: 1px solid var(--border);
        transform: translateX(110%); transition: transform .3s ease;
    }
    .nav-menu.open { transform: none; }
    .nav-menu li { width: 100%; }
    .nav-link { display: block; width: 100%; }
    .logo-sub { display: none; }
    .hamburger { display: flex; }
}
@media (max-width: 640px) {
    .highlights-grid { grid-template-columns: repeat(2, 1fr); gap: 24px; }
    .feature-grid { grid-template-columns: 1fr; }
    .backend-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; gap: 28px; }
    .section { padding: 70px 0; }
    .hero { padding: 140px 0 70px; }
}

@media (prefers-reduced-motion: reduce) {
    * { scroll-behavior: auto !important; }
    .reveal { opacity: 1; transform: none; transition: none; }
}