/* ============================================================
   BigDataCyberCloud — design system
   Dark, technical, enterprise. Matches RHC Solutions brand DNA:
   near-black base, green status accents, terminal/prompt motif.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&family=IBM+Plex+Sans:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;500;600&display=swap');

:root {
  /* base surfaces — cool near-black */
  --bg:        #080b11;
  --bg-2:      #0b0f17;
  --panel:     #0f141e;
  --panel-2:   #141b27;
  --panel-3:   #1a2331;
  --border:        rgba(255,255,255,0.08);
  --border-strong: rgba(255,255,255,0.15);

  /* text */
  --text:   #e7edf4;
  --dim:    #9aa8b8;
  --faint:  #667384;

  /* RHC brand green (the status-check accent) */
  --green:      oklch(0.74 0.16 152);
  --green-soft: oklch(0.74 0.16 152 / 0.14);
  --green-line: oklch(0.74 0.16 152 / 0.32);

  /* per-page accent — defaults to brand green, overridden by [data-topic] */
  --accent:      oklch(0.74 0.16 152);
  --accent-soft: oklch(0.74 0.16 152 / 0.13);
  --accent-line: oklch(0.74 0.16 152 / 0.34);
  --accent-glow: oklch(0.74 0.16 152 / 0.20);

  --maxw: 1180px;
  --radius: 14px;
  --radius-sm: 9px;

  --font-display: 'Space Grotesk', system-ui, sans-serif;
  --font-body: 'IBM Plex Sans', system-ui, sans-serif;
  --font-mono: 'IBM Plex Mono', ui-monospace, 'SF Mono', Menlo, monospace;
}

/* topic accents — equal chroma & lightness, hue varies */
[data-topic="bigdata"] { --accent: oklch(0.72 0.15 252); --accent-soft: oklch(0.72 0.15 252 / 0.13); --accent-line: oklch(0.72 0.15 252 / 0.34); --accent-glow: oklch(0.72 0.15 252 / 0.20); }
[data-topic="cyber"]   { --accent: oklch(0.74 0.16 152); --accent-soft: oklch(0.74 0.16 152 / 0.13); --accent-line: oklch(0.74 0.16 152 / 0.34); --accent-glow: oklch(0.74 0.16 152 / 0.20); }
[data-topic="cloud"]   { --accent: oklch(0.74 0.13 222); --accent-soft: oklch(0.74 0.13 222 / 0.13); --accent-line: oklch(0.74 0.13 222 / 0.34); --accent-glow: oklch(0.74 0.13 222 / 0.20); }
[data-topic="ai"]      { --accent: oklch(0.70 0.16 300); --accent-soft: oklch(0.70 0.16 300 / 0.13); --accent-line: oklch(0.70 0.16 300 / 0.34); --accent-glow: oklch(0.70 0.16 300 / 0.20); }

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

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

body {
  background:
    radial-gradient(1200px 700px at 80% -10%, var(--accent-glow), transparent 60%),
    radial-gradient(900px 600px at -10% 10%, rgba(255,255,255,0.03), transparent 55%),
    var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

/* subtle grid texture overlay */
body::before {
  content: "";
  position: fixed; inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.022) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.022) 1px, transparent 1px);
  background-size: 56px 56px;
  pointer-events: none;
  z-index: 0;
  mask-image: radial-gradient(120% 90% at 50% 0%, #000 35%, transparent 80%);
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

/* ---------- layout ---------- */
.wrap { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 28px; position: relative; z-index: 1; }
section { position: relative; z-index: 1; }
.pad { padding: clamp(56px, 9vw, 120px) 0; }
.pad-sm { padding: clamp(40px, 6vw, 72px) 0; }
.divide { border-top: 1px solid var(--border); }

/* ---------- eyebrow (terminal prompt motif) ---------- */
.eyebrow {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 18px;
}
.eyebrow::before { content: ">"; color: var(--accent); opacity: 0.8; }

/* ---------- type ---------- */
h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 600; line-height: 1.1; letter-spacing: -0.02em; color: #fff; }
h1 { font-size: clamp(38px, 5.6vw, 68px); }
h2 { font-size: clamp(28px, 3.6vw, 44px); }
h3 { font-size: clamp(20px, 2.2vw, 27px); letter-spacing: -0.015em; }
h4 { font-size: 19px; letter-spacing: -0.01em; }
p { color: var(--dim); }
.lead { font-size: clamp(18px, 1.7vw, 21px); color: var(--dim); line-height: 1.6; max-width: 62ch; }
.section-intro { max-width: 64ch; margin-top: 14px; }
strong { color: var(--text); font-weight: 600; }
.accent-text { color: var(--accent); }
.mono { font-family: var(--font-mono); }

/* ---------- nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in oklab, var(--bg) 78%, transparent);
  backdrop-filter: blur(14px) saturate(140%);
  border-bottom: 1px solid var(--border);
}
.nav-inner { display: flex; align-items: center; gap: 26px; height: 66px; }
.brand { display: flex; align-items: center; gap: 11px; font-family: var(--font-display); font-weight: 600; color: #fff; font-size: 17px; letter-spacing: -0.01em; white-space: nowrap; }
.brand .mark {
  width: 30px; height: 30px; border-radius: 8px; flex: none;
  background: linear-gradient(150deg, var(--panel-3), var(--panel));
  border: 1px solid var(--border-strong);
  display: grid; place-items: center;
  position: relative;
}
.brand .mark::before, .brand .mark::after { content:""; position:absolute; border-radius:2px; }
.brand .mark::before { width: 11px; height: 11px; border: 1.6px solid var(--green); border-radius: 3px; }
.brand .mark::after { width: 4px; height: 4px; background: var(--green); border-radius: 50%; box-shadow: 0 0 8px var(--green); }
.brand small { display:block; font-family: var(--font-mono); font-size: 10px; font-weight: 400; color: var(--faint); letter-spacing: 0.04em; margin-top: -2px; }
.nav-links { display: flex; gap: 4px; margin-left: auto; }
.nav-links a {
  font-size: 14.5px; color: var(--dim); padding: 8px 13px; border-radius: 8px;
  transition: color .15s, background .15s;
}
.nav-links a:hover { color: var(--text); background: var(--panel); }
.nav-links a.active { color: var(--text); }
.nav-links a.active::after { content:""; display:block; height:2px; margin-top:6px; border-radius:2px; background: var(--accent); }
.nav-cta { margin-left: 8px; }
.nav-burger { display: none; margin-left: auto; background: var(--panel); border: 1px solid var(--border); color: var(--text); width: 42px; height: 38px; border-radius: 9px; font-size: 18px; cursor: pointer; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 9px;
  font-family: var(--font-body); font-weight: 600; font-size: 15px;
  padding: 12px 20px; border-radius: 10px; cursor: pointer;
  border: 1px solid transparent; transition: transform .12s, background .15s, border-color .15s, box-shadow .2s;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--accent); color: #06120b; box-shadow: 0 0 0 1px var(--accent-line), 0 10px 30px -12px var(--accent); }
.btn-primary:hover { box-shadow: 0 0 0 1px var(--accent), 0 14px 36px -10px var(--accent-glow); filter: brightness(1.06); }
.btn-ghost { background: var(--panel); color: var(--text); border-color: var(--border-strong); }
.btn-ghost:hover { background: var(--panel-2); border-color: var(--accent-line); }
.btn-sm { padding: 9px 15px; font-size: 13.5px; }
.btn .arr { transition: transform .15s; }
.btn:hover .arr { transform: translateX(3px); }

/* ---------- cards & panels ---------- */
.card {
  background: linear-gradient(180deg, var(--panel), var(--bg-2));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
  position: relative;
  transition: border-color .2s, transform .2s, box-shadow .25s;
}
.card.hoverable:hover { border-color: var(--accent-line); transform: translateY(-3px); box-shadow: 0 24px 50px -28px rgba(0,0,0,0.8); }
.grid { display: grid; gap: 18px; }
.g2 { grid-template-columns: repeat(2, 1fr); }
.g3 { grid-template-columns: repeat(3, 1fr); }
.g4 { grid-template-columns: repeat(4, 1fr); }

.pill {
  display: inline-flex; align-items: center; gap: 7px;
  font-family: var(--font-mono); font-size: 12px; color: var(--dim);
  padding: 5px 11px; border-radius: 999px; border: 1px solid var(--border-strong); background: var(--panel);
}
.dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 8px var(--accent); flex: none; }
.dot.green { background: var(--green); box-shadow: 0 0 8px var(--green); }

.stat-num { font-family: var(--font-display); font-size: clamp(30px, 4vw, 46px); font-weight: 600; color: #fff; letter-spacing: -0.02em; line-height: 1; }
.stat-num .accent-text { color: var(--accent); }
.stat-label { color: var(--faint); font-size: 14px; margin-top: 8px; }

/* numbered/iconed feature row */
.feat { display: flex; gap: 16px; }
.feat .ix { flex: none; width: 40px; height: 40px; border-radius: 10px; background: var(--accent-soft); border: 1px solid var(--accent-line); color: var(--accent); display: grid; place-items: center; font-family: var(--font-mono); font-weight: 600; font-size: 15px; }

/* ---------- terminal component ---------- */
.terminal {
  background: linear-gradient(180deg, #0a0e15, #070a10);
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  overflow: hidden;
  font-family: var(--font-mono);
  box-shadow: 0 40px 90px -50px #000, inset 0 1px 0 rgba(255,255,255,0.04);
}
.term-bar { display: flex; align-items: center; gap: 8px; padding: 11px 14px; border-bottom: 1px solid var(--border); background: rgba(255,255,255,0.015); }
.term-bar .lights { display: flex; gap: 6px; }
.term-bar .lights i { width: 11px; height: 11px; border-radius: 50%; display: block; }
.term-bar .lights i:nth-child(1){ background:#ff5f57; } .term-bar .lights i:nth-child(2){ background:#febc2e; } .term-bar .lights i:nth-child(3){ background:#28c840; }
.term-bar .ttl { font-size: 12px; color: var(--faint); margin-left: 6px; }
.term-body { padding: 18px 18px 22px; font-size: 14px; line-height: 1.85; min-height: 220px; }
.term-body .ln { white-space: pre-wrap; }
.term-body .prompt { color: var(--accent); }
.term-body .ok { color: var(--green); }
.term-body .key { color: #cdd7e2; }
.term-body .mut { color: var(--faint); }
.cursor { display: inline-block; width: 8px; height: 1.05em; background: var(--accent); vertical-align: text-bottom; animation: blink 1.05s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }

/* ---------- tabs ---------- */
.tabs { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 22px; }
.tab {
  font-family: var(--font-mono); font-size: 13px; color: var(--dim);
  padding: 9px 15px; border-radius: 9px; border: 1px solid var(--border); background: var(--panel);
  cursor: pointer; transition: all .15s; display: inline-flex; align-items: center; gap: 8px;
}
.tab:hover { color: var(--text); border-color: var(--border-strong); }
.tab[aria-selected="true"] { color: var(--text); background: var(--accent-soft); border-color: var(--accent-line); }
.tab[aria-selected="true"] .tab-dot { background: var(--accent); box-shadow: 0 0 8px var(--accent); }
.tab-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--faint); }
.tabpanel { display: none; }
.tabpanel.active { display: block; }

/* ---------- accordion ---------- */
.acc-item { border: 1px solid var(--border); border-radius: 12px; background: var(--panel); margin-bottom: 12px; overflow: hidden; }
.acc-head { display: flex; align-items: center; gap: 14px; width: 100%; text-align: left; padding: 18px 22px; cursor: pointer; background: none; border: none; color: var(--text); font-family: var(--font-display); font-size: 18px; font-weight: 500; }
.acc-head .num { font-family: var(--font-mono); font-size: 13px; color: var(--accent); }
.acc-head .chev { margin-left: auto; transition: transform .25s; color: var(--faint); flex: none; }
.acc-item.open .acc-head .chev { transform: rotate(90deg); color: var(--accent); }
.acc-item.open { border-color: var(--accent-line); }
.acc-body { display: none; overflow: hidden; }
.acc-item.open .acc-body { display: block; }
.acc-body-inner { padding: 0 22px 22px 56px; color: var(--dim); }

/* ---------- diagram / nodes ---------- */
.diagram { background: linear-gradient(180deg, var(--bg-2), var(--bg)); border: 1px solid var(--border); border-radius: var(--radius); padding: 30px; }
.stage-row { display: flex; align-items: stretch; gap: 0; flex-wrap: wrap; }
.stage {
  flex: 1 1 0; min-width: 130px; cursor: pointer; text-align: center;
  padding: 20px 14px; border-radius: 12px; border: 1px solid var(--border); background: var(--panel);
  transition: all .2s; position: relative;
}
.stage:hover { border-color: var(--accent-line); }
.stage.active { border-color: var(--accent); background: var(--accent-soft); box-shadow: 0 0 0 1px var(--accent-line), 0 18px 40px -24px var(--accent-glow); }
.stage .s-ico { width: 46px; height: 46px; margin: 0 auto 12px; border-radius: 11px; background: var(--bg); border: 1px solid var(--border-strong); display: grid; place-items: center; color: var(--accent); }
.stage .s-name { font-family: var(--font-display); font-weight: 600; color: #fff; font-size: 16px; }
.stage .s-sub { font-family: var(--font-mono); font-size: 11px; color: var(--faint); margin-top: 3px; }
.stage-arrow { align-self: center; color: var(--faint); padding: 0 6px; flex: none; }
.stage-detail { margin-top: 22px; padding: 22px; border-radius: 12px; border: 1px solid var(--accent-line); background: var(--accent-soft); }
.stage-detail h4 { color: #fff; margin-bottom: 6px; }

/* ---------- range / calculator ---------- */
.calc { background: linear-gradient(180deg, var(--panel), var(--bg-2)); border: 1px solid var(--border); border-radius: var(--radius); padding: 28px; }
.field { margin-bottom: 22px; }
.field label { display: flex; justify-content: space-between; align-items: baseline; font-size: 14px; color: var(--dim); margin-bottom: 10px; font-weight: 500; }
.field label .val { font-family: var(--font-mono); color: var(--accent); font-size: 15px; }
input[type="range"] { -webkit-appearance: none; appearance: none; width: 100%; height: 6px; border-radius: 6px; background: var(--panel-3); outline: none; }
input[type="range"]::-webkit-slider-thumb { -webkit-appearance: none; width: 20px; height: 20px; border-radius: 50%; background: var(--accent); cursor: pointer; border: 3px solid var(--bg); box-shadow: 0 0 0 1px var(--accent-line), 0 0 12px var(--accent-glow); }
input[type="range"]::-moz-range-thumb { width: 20px; height: 20px; border-radius: 50%; background: var(--accent); cursor: pointer; border: 3px solid var(--bg); }
.calc-out { display: grid; gap: 14px; }
.calc-out .row { display: flex; justify-content: space-between; align-items: center; padding: 14px 16px; border-radius: 10px; background: var(--bg); border: 1px solid var(--border); }
.calc-out .row .k { color: var(--dim); font-size: 14px; }
.calc-out .row .v { font-family: var(--font-mono); color: #fff; font-size: 18px; font-weight: 500; }
.calc-out .row.hl { border-color: var(--accent-line); background: var(--accent-soft); }
.calc-out .row.hl .v { color: var(--accent); }
.seg { display: inline-flex; padding: 4px; gap: 4px; background: var(--bg); border: 1px solid var(--border); border-radius: 10px; }
.seg button { font-family: var(--font-mono); font-size: 13px; color: var(--dim); padding: 7px 14px; border-radius: 7px; border: none; background: none; cursor: pointer; transition: all .15s; }
.seg button[aria-pressed="true"] { background: var(--accent-soft); color: var(--accent); box-shadow: inset 0 0 0 1px var(--accent-line); }

/* ---------- quiz ---------- */
.quiz { background: linear-gradient(180deg, var(--panel), var(--bg-2)); border: 1px solid var(--border); border-radius: var(--radius); padding: 30px; }
.quiz .q-meta { display: flex; justify-content: space-between; align-items: center; font-family: var(--font-mono); font-size: 12px; color: var(--faint); margin-bottom: 14px; }
.quiz .q-bar { height: 4px; border-radius: 4px; background: var(--panel-3); overflow: hidden; margin-bottom: 22px; }
.quiz .q-bar i { display: block; height: 100%; background: var(--accent); transition: width .4s ease; }
.quiz .q-text { font-family: var(--font-display); font-size: 22px; font-weight: 600; color: #fff; margin-bottom: 20px; letter-spacing: -0.01em; }
.opts { display: grid; gap: 10px; }
.opt { display: flex; align-items: center; gap: 12px; padding: 15px 17px; border-radius: 11px; border: 1px solid var(--border); background: var(--bg); color: var(--text); cursor: pointer; text-align: left; font-size: 15.5px; transition: all .15s; font-family: var(--font-body); }
.opt:hover:not(:disabled) { border-color: var(--accent-line); background: var(--panel); }
.opt .mk { flex: none; width: 24px; height: 24px; border-radius: 6px; border: 1px solid var(--border-strong); display: grid; place-items: center; font-family: var(--font-mono); font-size: 12px; color: var(--faint); }
.opt.correct { border-color: var(--green-line); background: var(--green-soft); }
.opt.correct .mk { background: var(--green); border-color: var(--green); color: #06120b; }
.opt.wrong { border-color: oklch(0.65 0.2 25 / 0.4); background: oklch(0.65 0.2 25 / 0.1); }
.opt.wrong .mk { background: oklch(0.65 0.2 25); border-color: oklch(0.65 0.2 25); color: #fff; }
.quiz .explain { margin-top: 18px; padding: 16px 18px; border-radius: 11px; background: var(--bg); border: 1px solid var(--border); color: var(--dim); font-size: 14.5px; display: none; }
.quiz .explain.show { display: block; }
.quiz .explain b { color: var(--accent); }
.quiz-foot { display: flex; justify-content: space-between; align-items: center; margin-top: 22px; }
.quiz-result { text-align: center; padding: 20px 0; }
.quiz-result .big { font-family: var(--font-display); font-size: 52px; font-weight: 700; color: var(--accent); }

/* ---------- glossary term ---------- */
.term {
  border-bottom: 1px dashed var(--accent-line); color: var(--text); cursor: help; position: relative; font-weight: 500;
}
.term:hover { color: var(--accent); }
.gloss-pop {
  position: fixed; z-index: 80; max-width: 320px; padding: 14px 16px; border-radius: 11px;
  background: #0c111a; border: 1px solid var(--accent-line); box-shadow: 0 24px 60px -20px #000;
  font-size: 14px; color: var(--dim); line-height: 1.55; pointer-events: none; display: none;
}
.gloss-pop.show { display: block; }
.gloss-pop b { display: block; font-family: var(--font-mono); color: var(--accent); font-size: 13px; margin-bottom: 5px; }

/* ---------- CTA band ---------- */
.cta-band {
  border: 1px solid var(--accent-line); border-radius: 18px; padding: clamp(34px, 5vw, 56px);
  background:
    radial-gradient(700px 300px at 100% 0%, var(--accent-glow), transparent 60%),
    linear-gradient(180deg, var(--panel), var(--bg-2));
  position: relative; overflow: hidden;
}
.cta-band h2 { max-width: 18ch; }
.cta-band .btns { display: flex; gap: 12px; margin-top: 26px; flex-wrap: wrap; }
.affil { font-family: var(--font-mono); font-size: 12.5px; color: var(--faint); }
.affil a { color: var(--dim); border-bottom: 1px solid var(--border-strong); }
.affil a:hover { color: var(--accent); border-color: var(--accent-line); }

/* ---------- footer ---------- */
.footer { border-top: 1px solid var(--border); background: var(--bg-2); margin-top: 0; }
.footer .cols { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 32px; padding: 56px 0 40px; }
.footer h5 { font-family: var(--font-mono); font-size: 12px; color: var(--faint); text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 16px; font-weight: 500; }
.footer ul { list-style: none; display: grid; gap: 10px; }
.footer a { color: var(--dim); font-size: 14.5px; }
.footer a:hover { color: var(--accent); }
.footer .legal { border-top: 1px solid var(--border); padding: 22px 0; display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; font-size: 13px; color: var(--faint); }
.footer .legal .mono { font-size: 12.5px; }

/* ---------- reveal (base always visible; entrance is non-blocking) ---------- */
.reveal { opacity: 1; transform: none; }

/* ---------- domain card (landing) ---------- */
.domain { display: block; overflow: hidden; padding: 0; }
.domain .viz { height: 168px; border-bottom: 1px solid var(--border); position: relative; overflow: hidden; background: var(--bg); }
.domain .meta { padding: 22px 24px 26px; }
.domain .kicker { font-family: var(--font-mono); font-size: 12px; color: var(--accent); }
.domain h3 { margin: 7px 0 8px; }
.domain .go { margin-top: 16px; display: inline-flex; align-items: center; gap: 8px; font-family: var(--font-mono); font-size: 13px; color: var(--accent); }
.domain:hover .go .arr { transform: translateX(4px); }
.go .arr { transition: transform .15s; }

/* breadcrumb */
.crumbs { font-family: var(--font-mono); font-size: 13px; color: var(--faint); display: flex; gap: 9px; align-items: center; }
.crumbs a:hover { color: var(--accent); }
.crumbs .sep { opacity: 0.5; }

/* table of contents (sticky side) */
.guide-grid { display: grid; grid-template-columns: 220px 1fr; gap: 48px; align-items: start; }
.toc { position: sticky; top: 90px; }
.toc h5 { font-family: var(--font-mono); font-size: 11px; text-transform: uppercase; letter-spacing: 0.1em; color: var(--faint); margin-bottom: 14px; }
.toc a { display: block; font-size: 14px; color: var(--dim); padding: 7px 0 7px 14px; border-left: 2px solid var(--border); transition: all .15s; }
.toc a:hover { color: var(--text); border-color: var(--border-strong); }
.toc a.active { color: var(--accent); border-color: var(--accent); }

/* misc */
.kvs { display: grid; gap: 1px; background: var(--border); border: 1px solid var(--border); border-radius: 12px; overflow: hidden; }
.kvs .kv { display: flex; justify-content: space-between; gap: 16px; padding: 14px 18px; background: var(--panel); }
.kvs .kv .k { color: var(--dim); font-size: 14px; } .kvs .kv .v { font-family: var(--font-mono); color: var(--text); font-size: 14px; }
ul.ticks { list-style: none; display: grid; gap: 12px; }
ul.ticks li { display: flex; gap: 12px; color: var(--dim); }
ul.ticks li::before { content: "✓"; color: var(--accent); font-weight: 700; flex: none; }
.note { font-size: 13.5px; color: var(--faint); font-family: var(--font-mono); }

/* ---------- responsive ---------- */
@media (max-width: 920px) {
  .g4 { grid-template-columns: repeat(2, 1fr); }
  .g3 { grid-template-columns: 1fr; }
  .guide-grid { grid-template-columns: 1fr; }
  .toc { display: none; }
  .footer .cols { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 680px) {
  body { font-size: 16px; }
  .wrap { padding: 0 18px; }
  .nav-links { display: none; position: absolute; top: 66px; left: 0; right: 0; flex-direction: column; background: var(--bg-2); border-bottom: 1px solid var(--border); padding: 12px 18px; gap: 2px; }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px; }
  .nav-burger { display: block; }
  .nav-cta { display: none; }
  .g2, .g4 { grid-template-columns: 1fr; }
  .stage-arrow { display: none; }
  .stage { min-width: 100%; }
  .footer .cols { grid-template-columns: 1fr; gap: 24px; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: .001ms !important; transition-duration: .001ms !important; }
  .reveal { opacity: 1; transform: none; }
}