/* Hub styles for syntene.com. Tokens live in tokens.css. Black shell, green accent.
   Sections: shell, hero, depth, buttons, cards, steps, features, about, legal,
   footer, motion, responsive.
   2026-09-25 renovation: green (#34c759) is the one reward color; buttons are
   physical keys that travel into their edge; tiles lift on hover. */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display", "Segoe UI", Inter, sans-serif;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
/* One cheap fixed wash gives the page a lit-from-above feel. No repaint on scroll.
   A faint green halo at the top ties the page to the Learn dot. */
body::before {
  content: ""; position: fixed; inset: 0; z-index: 0; pointer-events: none;
  background: radial-gradient(920px 520px at 50% -12%, rgba(52, 199, 89, 0.12), transparent 68%);
}
.top, main, .foot { position: relative; z-index: 1; }

.top {
  display: flex; justify-content: space-between; align-items: center;
  padding-top: 14px; padding-bottom: 14px;
  padding-left: max(16px, env(safe-area-inset-left), calc((100% - 980px) / 2 + 16px));
  padding-right: max(16px, env(safe-area-inset-right), calc((100% - 980px) / 2 + 16px));
  border-bottom: 1px solid var(--line);
  position: -webkit-sticky; position: sticky; top: 0; z-index: 40; background: rgba(0, 0, 0, 0.86); -webkit-backdrop-filter: blur(10px); backdrop-filter: blur(10px);
}
@supports not ((backdrop-filter: blur(10px)) or (-webkit-backdrop-filter: blur(10px))) {
  .top { background: #000; }
}
.brand { letter-spacing: 0.25em; display: flex; gap: 10px; align-items: center; }
.logo { width: 34px; height: auto; display: block; flex: none; }
.name { font-size: 14px; }
.dot {
  display: inline-block; width: 8px; height: 8px; border-radius: 50%;
  background: var(--green); box-shadow: 0 0 10px var(--green-soft); flex: none;
}
.brand .dot { margin-left: 2px; }
nav { display: flex; gap: 16px; flex-wrap: wrap; justify-content: flex-end; }
nav a { position: relative; color: var(--muted); text-decoration: none; font-size: 14px; padding-bottom: 3px; transition: color 150ms var(--ease-out); }
nav a::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 2px; border-radius: 2px;
  background: var(--green); transform: scaleX(0); transform-origin: 50%;
  transition: transform 200ms var(--ease-out);
}
nav a:hover { color: var(--text); }
nav a:hover::after { transform: scaleX(1); }

main { max-width: 980px; margin: 0 auto; padding: 26px 16px 40px; }

/* Depth primitives. Transforms and opacity only, so every effect stays on the
   compositor. --rx/--ry/--gx/--gy are set by js/depth.js on fine pointers. */
[data-tilt] {
  --rx: 0deg; --ry: 0deg; --gx: 50%; --gy: 50%;
  transform: perspective(900px) rotateX(var(--rx)) rotateY(var(--ry));
  transform-style: preserve-3d;
  will-change: transform;
}
.sheen {
  position: absolute; inset: 0; border-radius: inherit; pointer-events: none; opacity: 0;
  background: radial-gradient(200px circle at var(--gx) var(--gy), rgba(255, 255, 255, 0.22), transparent 62%);
  transition: opacity 240ms var(--ease-out);
}
[data-tilt]:hover .sheen { opacity: 1; }

.hero { display: grid; gap: 30px; align-items: center; padding: 24px 0 6px; }
.hero-copy { max-width: 620px; }
.eyebrow { margin: 0; color: var(--muted); font-size: 12px; font-weight: 700; letter-spacing: 0.16em; text-transform: uppercase; }
h1 { font-size: clamp(36px, 7.5vw, 60px); line-height: 1.04; margin: 12px 0 0; font-weight: 800; letter-spacing: -0.03em; }
.sub { color: var(--muted); max-width: 540px; margin: 16px 0 0; font-size: 16px; line-height: 1.6; }
.cta-row { display: flex; gap: 12px; margin-top: 26px; flex-wrap: wrap; }
.hero-note { margin: 14px 0 0; color: var(--muted); font-size: 13px; letter-spacing: 0.02em; }

/* Hero: a real question you can answer. The card is a 3D key (data-tilt adds the
   perspective and pointer rotation); its own shadow gives it an extruded edge and
   a green floor glow. Answer, see why, then move on or open the full practice. */
.viz-wrap { display: grid; align-content: center; }
.qcard {
  position: relative; width: 100%; max-width: 460px; margin: 0 auto;
  display: grid; gap: 14px; padding: 20px;
  background: linear-gradient(180deg, #212126, #131316);
  border: 1px solid var(--ring); border-radius: 22px;
  box-shadow:
    inset 0 1px 0 var(--sheen),
    0 10px 0 -2px var(--bevel),
    0 30px 60px var(--shade);
}
.qcard::before {
  content: ""; position: absolute; left: 8%; right: 8%; bottom: -30px; height: 44px;
  background: radial-gradient(60% 100% at 50% 0%, var(--green-soft), transparent 72%);
  filter: blur(8px); pointer-events: none;
}
.qcard-head { display: flex; align-items: center; justify-content: space-between; gap: 10px; }
.qcard-topic { color: var(--accent-soft); font-size: 11px; font-weight: 800; letter-spacing: 0.16em; text-transform: uppercase; }
.qcard-diff { display: inline-flex; gap: 4px; }
.qcard-diff i { width: 7px; height: 7px; border-radius: 50%; background: rgba(255, 255, 255, 0.16); }
.qcard-diff i.on { background: var(--green); box-shadow: 0 0 8px var(--green-soft); }
.qcard-prompt { margin: 0; font-size: 17px; line-height: 1.5; font-weight: 700; color: var(--text); }
.qcard-opts { display: grid; gap: 8px; }
.qopt {
  --lift: 3px;
  display: grid; grid-template-columns: 26px 1fr; align-items: center; gap: 10px;
  padding: 11px 13px; border-radius: 13px; cursor: pointer;
  font: inherit; font-size: 15px; font-weight: 700; color: var(--text); text-align: left;
  background: linear-gradient(180deg, #2c2c31, #19191c);
  border: 1px solid var(--ring);
  box-shadow: inset 0 1px 0 var(--sheen-soft), 0 var(--lift) 0 var(--bevel);
  transform: translateY(0);
  transition: transform 120ms var(--spring), box-shadow 120ms var(--ease-out), border-color 160ms var(--ease-out), filter 160ms var(--ease-out);
}
.qopt:hover:not([disabled]) { transform: translateY(-1px); filter: brightness(1.14); border-color: rgba(255, 255, 255, 0.22); }
.qopt:active:not([disabled]) { transform: translateY(var(--lift)); box-shadow: inset 0 2px 5px rgba(0, 0, 0, 0.6), 0 1px 0 var(--bevel); transition-duration: 60ms; }
.qopt[disabled] { cursor: default; }
.qkey {
  display: grid; place-items: center; width: 26px; height: 26px; border-radius: 8px;
  background: rgba(255, 255, 255, 0.08); color: var(--muted); font-size: 12px; font-weight: 800;
}
.qopt.is-correct { border-color: var(--green); background: linear-gradient(180deg, rgba(52, 199, 89, 0.26), rgba(52, 199, 89, 0.10)); }
.qopt.is-correct .qkey { background: var(--green); color: var(--green-ink); }
.qopt.is-wrong { border-color: #ff5a5f; background: linear-gradient(180deg, rgba(255, 90, 95, 0.20), rgba(255, 90, 95, 0.06)); }
.qopt.is-wrong .qkey { background: #ff5a5f; color: #2a0507; }
.qcard-fb { margin: 0; min-height: 21px; font-size: 14px; line-height: 1.5; color: var(--muted); }
.qcard-fb.ok { color: var(--accent-soft); }
.qcard-fb.no { color: #ff9ba0; }
.qcard-foot { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; min-height: 40px; }
.qnext {
  --lift: 4px;
  padding: 10px 18px; border-radius: 12px; cursor: pointer;
  font: inherit; font-size: 14px; font-weight: 800; color: var(--green-ink);
  background: linear-gradient(180deg, var(--green-bright), var(--green));
  border: 1px solid rgba(255, 255, 255, 0.42);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.55), 0 var(--lift) 0 var(--green-edge);
  transition: transform 120ms var(--spring), box-shadow 120ms var(--ease-out), filter 160ms var(--ease-out);
}
.qnext:hover { transform: translateY(-1px); filter: brightness(1.05); }
.qnext:active { transform: translateY(var(--lift)); box-shadow: inset 0 2px 5px rgba(0, 0, 0, 0.3), 0 1px 0 var(--green-edge); transition-duration: 60ms; }
.qgo { font-size: 13px; font-weight: 700; letter-spacing: 0.03em; color: var(--muted); text-decoration: none; transition: color 150ms var(--ease-out); }
.qgo:hover { color: var(--green); }
/* A one-shot green ring on the card. Box-shadow only, so it never fights the
   tilt transform that js/depth.js is driving. */
@keyframes qflash {
  0%, 100% { box-shadow: inset 0 1px 0 var(--sheen), 0 10px 0 -2px var(--bevel), 0 30px 60px var(--shade); }
  40% { box-shadow: inset 0 1px 0 var(--sheen), 0 10px 0 -2px var(--bevel), 0 30px 60px var(--shade), 0 0 0 5px rgba(52, 199, 89, 0.30); }
}
.qcard.burst { animation: qflash 320ms var(--ease-out); }

/* Buttons: a real key. A hard edge sits under the face; pressing travels the
   full depth in 60ms, hovering lifts 2px and brightens. The solid key is green. */
.btn {
  --lift: 6px;
  position: relative; display: inline-flex; align-items: center; justify-content: center;
  min-height: 52px; padding: 0 30px; border-radius: 16px;
  font: inherit; font-size: 15px; font-weight: 800; letter-spacing: 0.01em;
  text-decoration: none; cursor: pointer; color: var(--text); text-align: center;
  background: linear-gradient(180deg, #2c2c31, #17171a);
  border: 1px solid var(--ring);
  box-shadow:
    inset 0 1px 0 var(--sheen),
    inset 0 -1px 0 rgba(0, 0, 0, 0.6),
    0 var(--lift) 0 var(--bevel),
    0 calc(var(--lift) + 10px) 22px var(--shade);
  transform: translateY(0);
  transition: transform 130ms var(--spring), box-shadow 130ms var(--ease-out), filter 180ms var(--ease-out), border-color 180ms var(--ease-out);
}
.btn:hover {
  transform: translateY(-2px) scale(1.015); filter: brightness(1.16);
  border-color: rgba(255, 255, 255, 0.22);
  box-shadow:
    inset 0 1px 0 var(--sheen),
    inset 0 -1px 0 rgba(0, 0, 0, 0.6),
    0 calc(var(--lift) + 2px) 0 var(--bevel),
    0 calc(var(--lift) + 16px) 30px var(--shade);
}
.btn:active {
  transform: translateY(var(--lift)) scale(0.99);
  box-shadow:
    inset 0 1px 0 var(--sheen-soft),
    inset 0 2px 6px rgba(0, 0, 0, 0.6),
    0 1px 0 var(--bevel),
    0 4px 10px var(--shade);
  transition-duration: 60ms;
}
.btn.solid {
  color: var(--green-ink);
  background: linear-gradient(180deg, var(--green-bright), var(--green));
  border-color: rgba(255, 255, 255, 0.45);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.55),
    inset 0 -2px 0 rgba(0, 0, 0, 0.18),
    0 var(--lift) 0 var(--green-edge),
    0 calc(var(--lift) + 10px) 26px rgba(0, 0, 0, 0.6);
}
.btn.solid:hover {
  filter: brightness(1.05) saturate(1.05);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.55),
    inset 0 -2px 0 rgba(0, 0, 0, 0.18),
    0 calc(var(--lift) + 2px) 0 var(--green-edge),
    0 calc(var(--lift) + 17px) 34px rgba(0, 0, 0, 0.62);
}
.btn.solid:active {
  box-shadow:
    inset 0 2px 6px rgba(0, 0, 0, 0.28),
    0 1px 0 var(--green-edge),
    0 4px 10px rgba(0, 0, 0, 0.5);
}

.cards { display: grid; gap: 14px; margin-top: 34px; grid-template-columns: 1fr; }
.card {
  position: relative; overflow: hidden;
  background: linear-gradient(180deg, #212126, #121215);
  border-radius: 24px; padding: 28px;
  display: grid; gap: 10px; align-content: start;
  border: 1px solid var(--ring);
  box-shadow: inset 0 1px 0 var(--sheen), 0 22px 50px var(--shade);
  text-decoration: none; color: var(--text);
  transition: border-color 200ms var(--ease-out), box-shadow 200ms var(--ease-out);
}
.card:hover { border-color: var(--green-soft); box-shadow: inset 0 1px 0 var(--sheen), 0 30px 60px var(--shade); }
.card .k { display: flex; align-items: center; gap: 8px; margin: 0; color: var(--muted); font-size: 11px; font-weight: 700; letter-spacing: 0.16em; text-transform: uppercase; }
.card .k::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: var(--green); box-shadow: 0 0 10px var(--green-soft); flex: none; }
.card h2 { margin: 0; font-size: 23px; font-weight: 800; letter-spacing: -0.01em; }
.card p { margin: 0; color: var(--muted); font-size: 15px; line-height: 1.62; max-width: 620px; }
.card .go { margin-top: 6px; font-size: 14px; font-weight: 700; letter-spacing: 0.04em; color: var(--accent-soft); }
.card:hover .go { color: var(--green); }
@media (min-width: 760px) { .card { padding: 32px; } }

.sec-h { display: flex; align-items: center; gap: 9px; margin: 0 0 14px; color: var(--muted); font-size: 11px; font-weight: 700; letter-spacing: 0.16em; text-transform: uppercase; }
.sec-h::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--green); flex: none; }

.steps { margin-top: 46px; border-top: 1px solid var(--line); padding-top: 26px; }
.steps-grid { display: grid; gap: 14px; grid-template-columns: 1fr; }
.step {
  background: linear-gradient(180deg, #16161a, #0e0e11);
  border: 1px solid var(--line); border-radius: 18px; padding: 20px;
  display: grid; gap: 8px; box-shadow: inset 0 1px 0 var(--sheen-soft);
  transition: border-color 200ms var(--ease-out);
}
.step:hover { border-color: var(--green-soft); }
.step .n { margin: 0; font-family: var(--mono); font-size: 12px; letter-spacing: 0.16em; color: var(--green); }
.step h3 { margin: 0; font-size: 18px; font-weight: 800; letter-spacing: -0.01em; }
.step p { margin: 0; color: var(--muted); font-size: 14.5px; line-height: 1.55; }

.features { margin-top: 40px; border-top: 1px solid var(--line); padding-top: 26px; }
.notes { margin-top: 40px; border-top: 1px solid var(--line); padding-top: 26px; }
.notes-grid { display: grid; gap: 14px; grid-template-columns: 1fr; }
.notes-grid p { margin: 0; color: var(--muted); font-size: 15px; line-height: 1.6; padding-left: 16px; border-left: 2px solid var(--green-soft); }

.about { margin-top: 40px; border-top: 1px solid var(--line); padding-top: 26px; }
.about p { color: var(--muted); font-size: 15.5px; line-height: 1.6; max-width: 640px; margin: 0; }

.legal h1 { font-size: clamp(26px, 5vw, 36px); }
.legal h2 { font-size: 17px; margin: 22px 0 6px; }
.legal p, .legal li { color: var(--muted); font-size: 15px; line-height: 1.6; }
.legal ul { padding-left: 20px; margin: 6px 0; display: grid; gap: 6px; }
.legal a { color: var(--accent-soft); text-decoration: underline; text-underline-offset: 2px; }
.legal a:hover { color: var(--green); }
.legal .legal-date { margin: 20px 0 0; font-size: 13px; color: var(--muted); opacity: 0.85; }
.panel.legal { background: var(--card); border-radius: 18px; padding: 22px; margin-top: 22px; }

.foot { max-width: 980px; margin: 28px auto 0; padding: 0 16px; }
.foot-grid { display: grid; gap: 22px; grid-template-columns: 1fr; padding-top: 26px; border-top: 1px solid var(--line-strong); }
.foot .logo { width: 28px; }
.foot-brand p { margin: 10px 0 0; color: var(--muted); font-size: 13.5px; line-height: 1.55; max-width: 300px; }
.foot-h { margin: 0 0 10px; color: var(--text); font-size: 11px; font-weight: 700; letter-spacing: 0.16em; text-transform: uppercase; }
.foot-col { display: grid; gap: 8px; align-content: start; justify-items: start; }
.foot-col a { color: var(--muted); text-decoration: none; font-size: 14px; padding: 3px 0; transition: color 150ms var(--ease-out); }
.foot-col a:hover { color: var(--green); }
.foot-base { margin-top: 26px; border-top: 1px solid var(--line-strong); padding-top: 16px; padding-bottom: max(8px, env(safe-area-inset-bottom)); display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; color: var(--muted); font-size: 12px; letter-spacing: 0.14em; text-transform: uppercase; }
.foot-base span:first-child { color: var(--accent-soft); }
.foot-base-right { display: inline-flex; align-items: center; gap: 16px; }

.intro { position: fixed; inset: 0; width: 100%; height: 100%; z-index: 100; background: #000; cursor: pointer; }

a:focus-visible, button:focus-visible, input:focus-visible {
  outline: 2px solid var(--accent); outline-offset: 3px;
}

/* Wider layouts: two columns from 820px, card grid, step and note grids. */
@media (min-width: 820px) {
  .hero { grid-template-columns: 1.12fr 0.88fr; gap: 44px; padding-top: 40px; }
}
@media (min-width: 760px) {
  .steps-grid { grid-template-columns: repeat(3, 1fr); }
  .notes-grid { grid-template-columns: 1fr 1fr; gap: 16px 30px; }
}
@media (min-width: 700px) {
  .foot-grid { grid-template-columns: 1.6fr 1fr 1fr; gap: 30px; }
}
@media (max-width: 820px) {
  .viz-wrap { order: 2; }
}
@media (max-width: 560px) {
  nav a[href="#how"], nav a[href="#about"] { display: none; }
}
@media (max-width: 520px) {
  main { padding-top: 20px; }
  .sub { font-size: 15px; }
  nav { gap: 12px; }
  .btn { width: 100%; padding: 0 22px; }
  .cta-row { gap: 10px; }
}
@media (max-width: 420px) {
  .top { flex-wrap: wrap; row-gap: 8px; }
  nav { gap: 12px; }
}

/* Motion off: drop the lift, the tilt and the scrub entirely. */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  [data-tilt] { transform: none !important; }
  .sheen { display: none; }
  nav a::after { display: none; }
  .btn, .card, .step, .foot-col a, nav a, .qopt, .qnext, .qgo { transition: none !important; }
  .btn:hover, .btn:active, .btn.solid:hover, .btn.solid:active { transform: none !important; }
  .qcard.burst { animation: none; }
  .qopt:hover:not([disabled]), .qopt:active:not([disabled]), .qnext:hover, .qnext:active { transform: none !important; }
}