/* ============================================================================
   3d.2nth.ai — shared design system
   Ported from the 2nth.ai palette used across know.2nth.ai / 2nth.ai so this
   property is visually part of the ecosystem. Linked by index.html and every
   leaf in /leaves so agents edit content, never the chrome.
   ========================================================================== */

:root {
  /* 2nth.ai palette */
  --ink: #0B1120;
  --ink-deep: #060A14;
  --navy: #121D33;
  --blue: #2563EB;
  --blue-glow: #3B82F6;
  --sky: #38BDF8;
  --sky-muted: #7DD3FC;
  --paper: #F8FAFC;
  --mist: #E2E8F0;
  --mist-dark: #334155;
  --slate: #94A3B8;
  --warm: #F59E0B;
  --warm-soft: rgba(245, 158, 11, 0.12);
  --green: #10B981;
  --green-soft: rgba(16, 185, 129, 0.12);
  --violet: #8B5CF6;
  --violet-soft: rgba(139, 92, 246, 0.12);
  --rose: #F43F5E;
  --rose-soft: rgba(244, 63, 94, 0.12);
  --code: #14B8A6;
  --code-soft: rgba(20, 184, 166, 0.12);
  --orange: #EA580C;
  --orange-soft: rgba(234, 88, 12, 0.12);

  /* Surfaces */
  --bg: var(--ink);
  --bg-raised: var(--navy);
  --bg-card: rgba(18, 29, 51, 0.7);
  --bg-card-hover: rgba(37, 99, 235, 0.08);
  --text-primary: var(--paper);
  --text-secondary: var(--slate);
  --text-muted: #64748B;
  --border: rgba(148, 163, 184, 0.1);
  --border-hover: rgba(56, 189, 248, 0.25);

  /* Sizing */
  --max-w: 1200px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-pill: 100px;
}

[data-theme="light"] {
  --bg: #F1F5F9;
  --bg-raised: #FFFFFF;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: rgba(37, 99, 235, 0.04);
  --text-primary: var(--ink);
  --text-secondary: #475569;
  --text-muted: #94A3B8;
  --border: rgba(15, 23, 42, 0.08);
  --border-hover: rgba(37, 99, 235, 0.2);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Outfit', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* ── Grain overlay ── */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  opacity: 0.025;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 9999;
}

/* ── Ambient glow ── */
.glow-orb { position: fixed; border-radius: 50%; filter: blur(120px); opacity: 0.08; pointer-events: none; z-index: 0; }
.glow-orb.blue { width: 600px; height: 600px; background: var(--blue); top: -200px; right: -100px; }
.glow-orb.sky { width: 500px; height: 500px; background: var(--sky); bottom: 20%; left: -150px; }
[data-theme="light"] .glow-orb { opacity: 0.04; }

/* ── Nav ── */
nav {
  position: sticky; top: 0; z-index: 100; padding: 0 24px;
  backdrop-filter: blur(20px) saturate(1.4);
  background: rgba(11, 17, 32, 0.75);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s ease;
}
[data-theme="light"] nav { background: rgba(241, 245, 249, 0.8); }
.nav-inner { max-width: var(--max-w); margin: 0 auto; display: flex; align-items: center; justify-content: space-between; height: 60px; }
.nav-brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text-primary); }
.nav-brand-mark {
  font-family: 'JetBrains Mono', monospace; font-weight: 600; font-size: 15px;
  background: linear-gradient(135deg, var(--blue), var(--sky));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; letter-spacing: -0.5px;
}
.nav-brand-sub { font-size: 12px; color: var(--text-muted); letter-spacing: 1.5px; text-transform: uppercase; font-weight: 500; padding-left: 10px; border-left: 1px solid var(--border); }
.nav-right { display: flex; align-items: center; gap: 16px; }
.nav-link { font-size: 13px; color: var(--text-secondary); text-decoration: none; font-weight: 500; transition: color 0.2s; }
.nav-link:hover { color: var(--sky); }
.theme-toggle { background: none; border: 1px solid var(--border); color: var(--text-secondary); width: 36px; height: 36px; border-radius: 50%; cursor: pointer; display: grid; place-items: center; font-size: 16px; transition: all 0.2s; }
.theme-toggle:hover { border-color: var(--border-hover); color: var(--sky); }
.btn-nav { font-size: 13px; font-weight: 600; padding: 8px 20px; border-radius: var(--radius-pill); border: none; cursor: pointer; text-decoration: none; transition: all 0.25s; }
.btn-nav-primary { background: linear-gradient(135deg, var(--blue), var(--blue-glow)); color: white; }
.btn-nav-primary:hover { transform: translateY(-1px); box-shadow: 0 4px 20px rgba(37, 99, 235, 0.3); }
.nav-toggle { display: none; background: none; border: 1px solid var(--border); color: var(--text-secondary); width: 38px; height: 38px; border-radius: 9px; cursor: pointer; font-size: 18px; line-height: 1; place-items: center; }
.nav-toggle:hover { border-color: var(--border-hover); color: var(--sky); }

/* ── Container ── */
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 24px; position: relative; z-index: 1; }

/* ── Hero ── */
.hero { padding: 100px 0 80px; text-align: center; position: relative; overflow: hidden; }
.vitruvian { position: absolute; top: 50%; left: 50%; width: 560px; height: 560px; transform: translate(-50%, -48%); pointer-events: none; z-index: 0; opacity: 0.09; color: var(--sky); }
[data-theme="light"] .vitruvian { opacity: 0.14; color: var(--blue); }
.vitruvian svg { width: 100%; height: 100%; display: block; }
.hero .container { position: relative; z-index: 1; }
@media (max-width: 640px) { .vitruvian { width: 380px; height: 380px; opacity: 0.07; } }

/* Live wireframe hero backdrop (canvas, ambient auto-rotation) */
.hero3d {
  position: absolute;
  top: 50%; left: 50%;
  width: 620px; height: 620px;
  transform: translate(-50%, -46%);
  pointer-events: none;
  z-index: 0;
  opacity: 0.42;
  -webkit-mask-image: radial-gradient(circle at 50% 50%, transparent 8%, #000 58%);
  mask-image: radial-gradient(circle at 50% 50%, transparent 8%, #000 58%);
}
[data-theme="light"] .hero3d { opacity: 0.5; }
@media (max-width: 640px) { .hero3d { width: 400px; height: 400px; opacity: 0.3; } }
.hero-eyebrow { font-family: 'JetBrains Mono', monospace; font-size: 12px; font-weight: 500; letter-spacing: 2px; text-transform: uppercase; color: var(--sky); margin-bottom: 20px; display: inline-flex; align-items: center; gap: 8px; }
.hero-eyebrow::before, .hero-eyebrow::after { content: ''; width: 24px; height: 1px; background: var(--sky); opacity: 0.4; }
.hero h1 { font-size: clamp(40px, 7vw, 72px); font-weight: 800; line-height: 1.05; letter-spacing: -2px; margin-bottom: 24px; }
.hero h1 .gradient { background: linear-gradient(135deg, var(--blue-glow), var(--sky), var(--sky-muted)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.hero-sub { font-size: 18px; color: var(--text-secondary); max-width: 600px; margin: 0 auto 40px; line-height: 1.7; font-weight: 300; }
.hero-ctas { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.byline { margin-top: 48px; display: inline-flex; align-items: center; gap: 14px; font-family: 'JetBrains Mono', monospace; font-size: 10.5px; letter-spacing: 1.6px; text-transform: uppercase; color: var(--text-muted); }
.byline::before, .byline::after { content: ''; width: 28px; height: 1px; background: var(--border); }
.byline strong { color: var(--text-secondary); font-weight: 500; letter-spacing: 1.8px; }

/* ── Buttons ── */
.btn { font-family: 'Outfit', sans-serif; font-size: 15px; font-weight: 600; padding: 14px 32px; border-radius: var(--radius-pill); border: none; cursor: pointer; text-decoration: none; transition: all 0.3s; display: inline-flex; align-items: center; gap: 8px; }
.btn-primary { background: linear-gradient(135deg, var(--blue), var(--blue-glow)); color: white; box-shadow: 0 2px 20px rgba(37, 99, 235, 0.2); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 30px rgba(37, 99, 235, 0.35); }
.btn-ghost { background: transparent; color: var(--text-primary); border: 1px solid var(--border); }
.btn-ghost:hover { border-color: var(--border-hover); background: var(--bg-card-hover); }

/* ── Section system ── */
section { padding: 80px 0; }
.section-label { font-family: 'JetBrains Mono', monospace; font-size: 11px; font-weight: 500; letter-spacing: 2px; text-transform: uppercase; color: var(--sky); margin-bottom: 12px; }
.section-title { font-size: clamp(28px, 4vw, 40px); font-weight: 700; letter-spacing: -1px; margin-bottom: 16px; line-height: 1.15; }
.section-desc { font-size: 16px; color: var(--text-secondary); max-width: 600px; line-height: 1.7; font-weight: 300; }
.section-header { margin-bottom: 48px; }

/* ── How it works ── */
.logic-flow { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 2px; }
.logic-step { background: var(--bg-card); backdrop-filter: blur(10px); border: 1px solid var(--border); padding: 32px 24px; text-align: center; position: relative; transition: all 0.3s; }
.logic-step:first-child { border-radius: var(--radius-lg) 0 0 var(--radius-lg); }
.logic-step:last-child { border-radius: 0 var(--radius-lg) var(--radius-lg) 0; }
.logic-step:hover { background: var(--bg-card-hover); border-color: var(--border-hover); }
.logic-num { font-family: 'JetBrains Mono', monospace; font-size: 32px; font-weight: 700; background: linear-gradient(135deg, var(--blue), var(--sky)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; margin-bottom: 8px; }
.logic-label { font-size: 14px; font-weight: 600; margin-bottom: 6px; }
.logic-detail { font-size: 12px; color: var(--text-muted); line-height: 1.5; }
.logic-arrow { position: absolute; right: -12px; top: 50%; transform: translateY(-50%); color: var(--sky); font-size: 18px; z-index: 2; opacity: 0.6; }

/* ── Domain / category browser ── */
.domains-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(340px, 1fr)); gap: 16px; }
.domain-card { background: var(--bg-card); backdrop-filter: blur(10px); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 32px; transition: all 0.35s; cursor: pointer; position: relative; overflow: hidden; text-decoration: none; color: inherit; display: block; }
.domain-card:hover { border-color: var(--border-hover); transform: translateY(-3px); box-shadow: 0 12px 40px rgba(0, 0, 0, 0.15); }
.domain-card::after { content: ''; position: absolute; inset: 0; background: linear-gradient(135deg, transparent 60%, var(--card-accent, transparent)); opacity: 0.06; transition: opacity 0.3s; }
.domain-card:hover::after { opacity: 0.1; }
.domain-icon { width: 48px; height: 48px; border-radius: var(--radius-md); display: grid; place-items: center; font-size: 22px; margin-bottom: 20px; position: relative; }
.domain-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 8px; letter-spacing: -0.3px; }
.domain-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.6; margin-bottom: 20px; }
.skill-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.skill-tag { font-family: 'JetBrains Mono', monospace; font-size: 11px; font-weight: 500; padding: 4px 12px; border-radius: var(--radius-pill); border: 1px solid var(--border); color: var(--text-muted); transition: all 0.2s; }
.domain-card:hover .skill-tag { border-color: var(--border-hover); color: var(--text-secondary); }
.domain-count { font-family: 'JetBrains Mono', monospace; font-size: 11px; color: var(--text-muted); position: absolute; top: 32px; right: 32px; }

/* Coming-soon state */
.domain-card.soon, .explainer-card.soon { cursor: default; opacity: 0.72; }
.domain-card.soon:hover, .explainer-card.soon:hover { transform: none; border-color: var(--border); box-shadow: none; background: transparent; }
.domain-card.soon .domain-count, .explainer-card.soon .explainer-tier-tag { color: var(--text-muted); border-style: dashed; border-color: var(--border); }

/* Category accents (the five 3d.2nth.ai doors) */
.domain-card[data-domain="cad"]         { --card-accent: var(--blue); }
.domain-card[data-domain="cad"] .domain-icon         { background: rgba(37, 99, 235, 0.1);  color: var(--blue-glow); }
.domain-card[data-domain="printing"]    { --card-accent: var(--sky); }
.domain-card[data-domain="printing"] .domain-icon    { background: rgba(56, 189, 248, 0.1);  color: var(--sky); }
.domain-card[data-domain="cnc"]         { --card-accent: var(--orange); }
.domain-card[data-domain="cnc"] .domain-icon         { background: var(--orange-soft);       color: var(--orange); }
.domain-card[data-domain="ai3d"]        { --card-accent: var(--violet); }
.domain-card[data-domain="ai3d"] .domain-icon        { background: var(--violet-soft);       color: var(--violet); }
.domain-card[data-domain="engineering"] { --card-accent: var(--green); }
.domain-card[data-domain="engineering"] .domain-icon { background: var(--green-soft);        color: var(--green); }

/* ── Featured explainer cards ── */
.explainer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 16px; }
.explainer-card { background: var(--bg-card); backdrop-filter: blur(10px); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 28px; transition: all 0.3s; text-decoration: none; color: inherit; display: block; }
.explainer-card:hover { border-color: var(--border-hover); transform: translateY(-2px); }
.explainer-meta { display: flex; align-items: center; gap: 8px; margin-bottom: 14px; }
.explainer-domain-tag { font-family: 'JetBrains Mono', monospace; font-size: 10px; font-weight: 600; letter-spacing: 1px; text-transform: uppercase; padding: 3px 10px; border-radius: var(--radius-pill); background: rgba(56, 189, 248, 0.1); color: var(--sky); }
.explainer-tier-tag { font-family: 'JetBrains Mono', monospace; font-size: 10px; padding: 3px 8px; border-radius: var(--radius-pill); border: 1px solid var(--border); color: var(--text-muted); }
.explainer-card h4 { font-size: 17px; font-weight: 600; margin-bottom: 8px; letter-spacing: -0.2px; }
.explainer-card p { font-size: 13px; color: var(--text-muted); line-height: 1.5; }

/* ── Subscribe block ── */
.subscribe-block { background: var(--bg-card); backdrop-filter: blur(10px); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 48px; text-align: center; position: relative; overflow: hidden; }
.subscribe-block::before { content: ''; position: absolute; inset: 0; background: linear-gradient(135deg, rgba(37, 99, 235, 0.05), rgba(56, 189, 248, 0.05), rgba(139, 92, 246, 0.05)); }
.subscribe-block > * { position: relative; }
.subscribe-form { display: flex; gap: 10px; max-width: 460px; margin: 24px auto 0; flex-wrap: wrap; justify-content: center; }
.subscribe-form input[type="email"] { flex: 1; min-width: 220px; font-family: 'Outfit', sans-serif; font-size: 15px; padding: 13px 18px; border-radius: var(--radius-pill); border: 1px solid var(--border); background: var(--bg); color: var(--text-primary); }
.subscribe-form input[type="email"]:focus { outline: none; border-color: var(--border-hover); }
.subscribe-note { font-size: 12px; color: var(--text-muted); margin-top: 14px; }
.form-msg { font-size: 13px; margin-top: 14px; min-height: 18px; }
.form-msg.ok { color: var(--green); }
.form-msg.err { color: var(--rose); }

/* ── Leaf article ── */
.leaf { max-width: 760px; margin: 0 auto; padding: 60px 24px 40px; }
.leaf .breadcrumb { font-family: 'JetBrains Mono', monospace; font-size: 12px; color: var(--text-muted); margin-bottom: 24px; }
.leaf .breadcrumb a { color: var(--text-secondary); text-decoration: none; }
.leaf .breadcrumb a:hover { color: var(--sky); }
.leaf h1 { font-size: clamp(32px, 5vw, 48px); font-weight: 800; letter-spacing: -1.5px; line-height: 1.1; margin-bottom: 16px; }
.leaf .lede { font-size: 19px; color: var(--text-secondary); font-weight: 300; line-height: 1.7; margin-bottom: 32px; }
.leaf h2 { font-size: 26px; font-weight: 700; letter-spacing: -0.5px; margin: 40px 0 14px; }
.leaf h3 { font-size: 19px; font-weight: 600; margin: 28px 0 10px; }
.leaf p { font-size: 16px; color: var(--text-secondary); line-height: 1.8; margin-bottom: 16px; }
.leaf ul, .leaf ol { color: var(--text-secondary); line-height: 1.8; margin: 0 0 16px 22px; }
.leaf li { margin-bottom: 6px; }
.leaf a { color: var(--sky); text-decoration: none; border-bottom: 1px solid transparent; }
.leaf a:hover { border-bottom-color: var(--sky); }
.leaf code { font-family: 'JetBrains Mono', monospace; font-size: 0.88em; background: var(--bg-card); padding: 2px 7px; border-radius: 6px; border: 1px solid var(--border); }
.leaf pre { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-md); padding: 18px; overflow-x: auto; margin-bottom: 16px; }
.leaf pre code { background: none; border: none; padding: 0; }
.leaf blockquote { border-left: 3px solid var(--sky); padding-left: 18px; margin: 0 0 16px; color: var(--text-secondary); font-style: italic; }
.factbar { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 32px; }
.fact { font-family: 'JetBrains Mono', monospace; font-size: 11px; padding: 5px 12px; border-radius: var(--radius-pill); border: 1px solid var(--border); color: var(--text-secondary); }
.fact strong { color: var(--text-primary); }
.fact.oss { color: var(--green); border-color: rgba(16,185,129,0.3); }
.fact.ai { color: var(--violet); border-color: rgba(139,92,246,0.3); }
.tldr { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-md); padding: 20px 24px; margin-bottom: 32px; }
.tldr .mono-label { font-family: 'JetBrains Mono', monospace; font-size: 11px; font-weight: 600; letter-spacing: 1.5px; text-transform: uppercase; color: var(--sky); display: block; margin-bottom: 8px; }
.tldr p { margin: 0; font-size: 15px; }

/* ── Footer ── */
footer { padding: 60px 0 40px; border-top: 1px solid var(--border); text-align: center; }
.footer-brand { font-family: 'JetBrains Mono', monospace; font-size: 14px; font-weight: 600; background: linear-gradient(135deg, var(--blue), var(--sky)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; margin-bottom: 8px; }
.footer-tagline { font-size: 13px; color: var(--text-muted); margin-bottom: 24px; }
.footer-links { display: flex; justify-content: center; gap: 24px; margin-bottom: 24px; flex-wrap: wrap; }
.footer-links a { font-size: 13px; color: var(--text-secondary); text-decoration: none; transition: color 0.2s; }
.footer-links a:hover { color: var(--sky); }
.footer-copy { font-size: 12px; color: var(--text-muted); }

/* ── Fade-in ── */
.fade-up { opacity: 0; transform: translateY(24px); transition: opacity 0.6s ease, transform 0.6s ease; }
.fade-up.visible { opacity: 1; transform: translateY(0); }

/* ── Responsive ── */
@media (max-width: 768px) {
  .hero { padding: 60px 0 50px; }
  .logic-flow { grid-template-columns: 1fr; }
  .logic-step:first-child { border-radius: var(--radius-lg) var(--radius-lg) 0 0; }
  .logic-step:last-child { border-radius: 0 0 var(--radius-lg) var(--radius-lg); }
  .logic-arrow { display: none; }
  .domains-grid { grid-template-columns: 1fr; }
  .nav-brand-sub { display: none; }
  .nav-toggle { display: grid; }
  .nav-right {
    position: absolute; top: 60px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: rgba(11, 17, 32, 0.98); border-bottom: 1px solid var(--border);
    padding: 8px 0; display: none;
  }
  [data-theme="light"] .nav-right { background: rgba(241, 245, 249, 0.98); }
  nav.nav-open .nav-right { display: flex; }
  .nav-right .nav-link { font-size: 16px; padding: 13px 24px; }
  .nav-right .theme-toggle { margin: 8px 24px; width: auto; border-radius: 9px; height: 40px; }
  .nav-right .btn-nav { margin: 8px 24px; text-align: center; padding: 12px 20px; }
  .subscribe-block { padding: 32px 20px; }
}

*, *::before, *::after { transition-property: background-color, border-color, color, box-shadow; transition-duration: 0.3s; transition-timing-function: ease; }