:root {
  color-scheme: dark;
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --hue: 168;
  --canvas: hsl(168 28% 6%);
  --panel: hsl(168 26% 9% / 0.58);
  --floor: hsl(168 28% 7% / 0.78);
  --line: rgba(255,255,255,.09);
  --line-strong: rgba(255,255,255,.18);
  --text: rgba(255,255,255,.94);
  --muted: rgba(255,255,255,.48);
  --accent: hsl(168 72% 68%);
  --accent-2: hsl(168 62% 52%);
  --accent-surface: hsl(168 62% 52% / 0.16);
  --good: #73e6b1;
  --warn: #f0c36a;
  --danger: #ff8181;
  --radius: 10px;
  --control: 9px;
  --target: 44px;
  --direct: 180ms;
  --scene: 520ms;
  --left-rail: 252px;
  --right-rail: 216px;
  --inspect-sheet: min(420px, 92vw);
  --top-rail: 66px;
  --floor-h: 30px;
  --edge-sensor: 28px;
}
* { box-sizing: border-box; }
html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background: var(--canvas);
  color: var(--text);
}
body {
  min-height: 100vh;
  background:
    radial-gradient(circle at 72% 18%, hsl(168 72% 68% / .14), transparent 28rem),
    radial-gradient(circle at 32% 72%, hsl(168 42% 32% / .18), transparent 30rem),
    var(--canvas);
}
button, select { font: inherit; color: inherit; }
button { cursor: pointer; }

.board {
  position: relative;
  height: 100vh;
  overflow: hidden;
  display: grid;
  grid-template-rows: var(--top-rail) 1fr;
}
.topbar {
  min-height: var(--top-rail);
  display: flex;
  gap: 16px;
  align-items: center;
  justify-content: space-between;
  padding: 8px 18px;
  border-bottom: 1px solid var(--line);
  background: hsl(168 28% 8% / 0.42);
  backdrop-filter: blur(18px);
  z-index: 20;
}
.identity { display: flex; align-items: center; gap: 12px; }
.mark {
  width: var(--target); height: var(--target); display: grid; place-items: center;
  border: 1px solid hsl(168 72% 68% / .5);
  border-radius: 14px;
  background: linear-gradient(145deg, hsl(168 62% 52% / .32), hsl(168 28% 8% / .1));
  font-weight: 800;
}
h1, h2, h3, p { margin: 0; }
h1 { font-size: 22px; letter-spacing: -.035em; }
h2 { font-size: 18px; letter-spacing: -.025em; }
h3 { font-size: 24px; letter-spacing: -.035em; }
.eyebrow { color: var(--muted); font-size: 11px; text-transform: uppercase; letter-spacing: .13em; margin-bottom: 4px; }
.phase { color: var(--warn); font-size: 13px; }

.canvas { min-height: 0; padding: 10px 74px 10px; }
.stage {
  height: 100%;
  display: grid;
  grid-template-rows: auto 1fr auto;
  border: 1px solid var(--line);
  background: hsl(168 28% 8% / 0.42);
  backdrop-filter: blur(16px);
  border-radius: var(--radius);
  overflow: hidden;
}
.stage-head { display: flex; align-items: center; justify-content: space-between; padding: 12px 18px; border-bottom: 1px solid var(--line); }
.position { color: var(--muted); font-size: 12px; }

.scene {
  position: relative; min-height: 0; overflow: hidden; outline: none; perspective: 1300px;
  background:
    linear-gradient(180deg, rgba(255,255,255,.018), rgba(0,0,0,.08)),
    radial-gradient(circle at 50% 50%, hsl(168 62% 52% / .10), transparent 42%);
}
.scene:focus-visible { box-shadow: inset 0 0 0 2px hsl(168 72% 68% / .7); }
.ambient { position: absolute; width: 380px; height: 380px; border-radius: 50%; filter: blur(68px); opacity: .16; pointer-events: none; }
.ambient-one { background: var(--accent); top: -190px; right: -100px; }
.ambient-two { background: var(--accent-2); left: -210px; bottom: -220px; }
.cards { position: absolute; inset: 0; display: grid; place-items: center; transform-style: preserve-3d; }
.flow-card {
  position: absolute;
  width: min(74%, 520px); min-height: 300px;
  border: 1px solid var(--line-strong);
  border-radius: 30px;
  background:
    linear-gradient(155deg, rgba(255,255,255,.10), rgba(255,255,255,.025) 46%, rgba(0,0,0,.18)),
    hsl(168 28% 8% / .96);
  box-shadow: 0 40px 90px rgba(0,0,0,.44);
  padding: 30px;
  transform-style: preserve-3d;
  transition:
    transform var(--scene) cubic-bezier(.2,.8,.2,1),
    opacity var(--scene) ease,
    filter var(--scene) ease;
  opacity: 0;
  pointer-events: none;
  display: flex; flex-direction: column; justify-content: space-between;
}
.flow-card[data-state="active"] {
  opacity: 1; pointer-events: auto;
  transform: translate3d(0, 0, 80px) rotateX(0) rotateY(0) scale(1);
  filter: blur(0);
}
.flow-card[data-state="past"] {
  opacity: .08;
  transform: translate3d(-42%, -5%, -160px) rotateY(20deg) scale(.84);
  filter: blur(2px);
}
.flow-card[data-state="future"] {
  opacity: .22;
  transform: translate3d(25%, 8%, -110px) rotateY(-14deg) scale(.88);
  filter: blur(1px);
}
.card-kicker { font-size: 12px; color: var(--accent); text-transform: uppercase; letter-spacing: .13em; }
.card-title { font-size: clamp(32px, 5vw, 58px); line-height: .98; letter-spacing: -.055em; margin-top: 18px; max-width: 12ch; }
.card-impl { margin-top: 14px; color: var(--muted); font-size: 14px; line-height: 1.45; max-width: 36ch; }
.card-foot { display: flex; justify-content: space-between; align-items: end; gap: 18px; color: var(--muted); font-size: 12px; }
.card-id { font-family: "SFMono-Regular", Consolas, monospace; color: #d5d9e5; }
.card-role { text-transform: uppercase; letter-spacing: .11em; }
.empty-state { position: absolute; inset: 0; display: grid; place-content: center; text-align: center; padding: 20px; color: var(--muted); }
.empty-state.hidden { display: none; }
.empty-symbol { color: var(--accent); font-size: 42px; margin-bottom: 10px; }
.empty-state p { max-width: 42ch; line-height: 1.55; margin-top: 8px; }

.deck-controls {
  min-height: var(--target);
  display: grid;
  grid-template-columns: var(--target) 1fr var(--target);
  align-items: center;
  gap: 12px;
  width: min(300px, 92%);
  margin: 8px auto 12px;
  padding: 0;
}
.deck-controls button {
  width: var(--target); height: var(--target); border-radius: 14px; border: 1px solid var(--line);
  background: rgba(255,255,255,.04); transition: background var(--direct), transform var(--direct);
}
.deck-controls button:hover { background: rgba(255,255,255,.09); transform: translateY(-1px); }
.deck-controls button:disabled { opacity: .28; cursor: default; transform: none; }
.progress { display: flex; justify-content: center; gap: 7px; min-width: 0; }
.progress button {
  width: 8px; height: 8px; min-width: 8px; border: 0; padding: 0; border-radius: 999px;
  background: rgba(255,255,255,.18); transition: width var(--direct), background var(--direct);
}
.progress button.active { width: 26px; background: linear-gradient(90deg, var(--accent), var(--accent-2)); }

.edge {
  position: absolute;
  top: calc(var(--top-rail) + 10px);
  width: 64px;
  min-height: var(--target);
  z-index: 15;
  border: 1px solid var(--line);
  border-radius: var(--control);
  background: var(--accent-surface);
  writing-mode: vertical-rl;
  letter-spacing: .14em;
  text-transform: uppercase;
  font-size: 11px;
}
.edge-left { left: 10px; }
.edge-right { right: 10px; }
.edge[aria-expanded="true"] { visibility: hidden; }

.scrim {
  position: absolute; inset: var(--top-rail) 0 0;
  background: hsl(168 28% 4% / .35);
  z-index: 24;
  pointer-events: none;
}
.drawer {
  position: absolute;
  top: var(--top-rail);
  bottom: 0;
  z-index: 30;
  background: hsl(168 28% 7% / 0.96);
  border: 1px solid var(--line);
  padding: 16px;
  overflow: auto;
  opacity: 0;
  pointer-events: none;
  transition: transform var(--direct) ease-out, opacity var(--direct) ease-out;
}
.source-rail {
  left: 10px;
  width: var(--left-rail);
  transform: translateX(calc(-100% - 16px));
}
.inspect-rail {
  right: 10px;
  width: var(--inspect-sheet);
  transform: translateX(calc(100% + 16px));
}
.drawer[data-open="true"] {
  opacity: 1;
  pointer-events: auto;
  transform: translateX(0);
}
.panel-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.icon-close {
  min-height: var(--target); min-width: var(--target);
  border-radius: var(--control); border: 1px solid var(--line); background: transparent;
}
.field-label { display: block; margin-top: 14px; margin-bottom: 6px; color: var(--muted); font-size: 11px; text-transform: uppercase; letter-spacing: .11em; }
select {
  width: 100%; min-height: var(--target); border: 1px solid var(--line); outline: none;
  border-radius: var(--control); background: rgba(0,0,0,.22); padding: 8px 10px;
}
select:focus { border-color: hsl(168 72% 68% / .55); box-shadow: 0 0 0 3px hsl(168 62% 52% / .16); }
.hint { margin-top: 12px; color: var(--muted); font-size: 12px; line-height: 1.55; }
.hint code { color: var(--accent); }
.source-block {
  margin: 8px 0 0; padding: 12px; border-radius: var(--control); border: 1px solid var(--line);
  background: rgba(0,0,0,.22); color: #dce2ef; font-size: 11px; line-height: 1.5;
  white-space: pre; overflow-x: auto;
}
.inspect-rail dl { margin: 18px 0 0; }
.inspect-rail dl > div { padding: 12px 0; border-bottom: 1px solid var(--line); }
dt { color: var(--muted); font-size: 11px; text-transform: uppercase; letter-spacing: .12em; }
dd { margin: 5px 0 0; font-size: 14px; }
.hash { font-family: "SFMono-Regular", Consolas, monospace; font-size: 10px; line-height: 1.45; overflow-wrap: anywhere; }
.transition-reading {
  margin-top: 18px; padding: 14px; border-radius: 16px;
  background: var(--accent-surface); color: #c9cfdd; font-size: 12px; line-height: 1.55;
  border: 1px solid hsl(168 72% 68% / .12);
}
.tabs { display: flex; flex-wrap: wrap; gap: 8px; margin: 16px 0 8px; }
.tabs button {
  min-height: var(--target); border-radius: 999px; border: 1px solid var(--line);
  background: transparent; padding: 0 14px;
}
.tabs button[aria-selected="true"] { background: var(--accent-surface); border-color: var(--accent); }
.panel { min-height: 160px; white-space: pre-wrap; line-height: 1.45; font-size: 13px; }

@media (max-width: 760px) {
  .canvas { padding: 8px; }
  .edge { display: none; }
  .source-rail, .inspect-rail { width: min(92vw, 320px); }
  .flow-card { width: 86%; min-height: 280px; padding: 24px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 1ms !important; animation-duration: 1ms !important; }
}