:root {
  --bg: #0b0c0b;
  --panel: #141714;
  --mat: #101210;
  --ink: #f4f1e6;
  --muted: #8f9688;
  --line: #262b24;
  --accent: #c8f542;
  --accent-ink: #14180a;
  --ok: #c8f542;
  --warn: #ff5a3c;
  --sidebar: #070807;
  --sans: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Avenir Next", ui-sans-serif, system-ui, sans-serif;
  --mono: "SF Mono", ui-monospace, Menlo, monospace;
  --sidebar-w: 228px;
  --hard: 3px;
}

* { box-sizing: border-box; }
html, body { margin: 0; min-height: 100%; }
body {
  color: var(--ink);
  background-color: var(--bg);
  background-image:
    radial-gradient(ellipse 1100px 480px at 78% -8%, rgba(200,245,66,.07), transparent 58%),
    radial-gradient(ellipse 720px 420px at 6% 108%, rgba(80,36,8,.16), transparent 52%),
    radial-gradient(circle at center, rgba(22,24,20,.9) 1.15px, transparent 1.35px);
  background-size: auto, auto, 8px 8px;
  font: 17px/1.55 var(--sans);
}
a { color: var(--accent); }
a:focus-visible, button:focus-visible, input:focus-visible, textarea:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}
.skip { position: absolute; left: -999px; }
.skip:focus { left: 8px; top: 8px; background: var(--accent); color: var(--accent-ink); padding: 8px 12px; z-index: 10; }

.shell {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  min-height: 100vh;
}
.side {
  background: var(--sidebar);
  border-right: 1px solid var(--line);
  padding: 28px 14px 36px 16px;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: auto;
}
.brand {
  display: block;
  color: var(--ink);
  text-decoration: none;
  font: 900 28px/1 var(--sans);
  letter-spacing: -0.05em;
}
.brand small {
  display: inline-block;
  margin-top: 10px;
  padding: 4px 8px;
  background: var(--accent);
  color: var(--accent-ink);
  font: 800 10px/1 var(--sans);
  letter-spacing: 0.22em;
}
.side nav { margin-top: 16px; display: grid; gap: 1px; }
.side nav a {
  color: var(--muted);
  text-decoration: none;
  padding: 9px 10px 9px 12px;
  border-radius: var(--hard);
  font-size: 14px;
  font-weight: 650;
  border-left: 3px solid transparent;
}
.side nav a:hover { color: var(--ink); background: #121512; }
.side nav a[aria-current="page"] {
  background: rgba(200,245,66,.1);
  color: var(--ink);
  border-left-color: var(--accent);
}
.side .group {
  margin: 24px 0 8px 12px;
  color: #6b7264;
  font: 800 10px/1 var(--sans);
  letter-spacing: 0.22em;
  text-transform: uppercase;
}
.side .note { margin: 32px 12px 0; color: var(--muted); font-size: 12px; line-height: 1.5; }

.top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 40px;
  border-bottom: 1px solid var(--line);
  background: rgba(8,10,8,.55);
}
.top strong { font: 800 13px/1 var(--sans); letter-spacing: 0.14em; color: var(--muted); }
.top a { color: var(--muted); text-decoration: none; font-size: 14px; font-weight: 700; margin-left: 22px; }
.top a:hover { color: var(--accent); }
.top .links { display: flex; align-items: center; }

main.page, main.lesson {
  width: min(1180px, calc(100% - 80px));
  margin: 0 auto;
  padding: 36px 0 88px;
}
main.lesson {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(300px, 0.95fr);
  column-gap: 40px;
}

.kicker {
  margin: 0 0 12px;
  color: var(--accent);
  font: 800 12px/1 var(--sans);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  grid-column: 1 / -1;
  display: inline-flex;
  align-items: center;
  gap: 10px;
}
.kicker::before {
  content: "";
  width: 22px;
  height: 3px;
  background: var(--accent);
}
h1 {
  margin: 0 0 14px;
  font: 900 46px/1.06 var(--sans);
  letter-spacing: -0.05em;
  max-width: 18em;
  grid-column: 1 / -1;
}
.lede {
  margin: 0 0 26px;
  max-width: 38em;
  font-size: 18px;
  line-height: 1.5;
  color: var(--muted);
  grid-column: 1 / -1;
}
h2 {
  font: 800 22px/1.25 var(--sans);
  margin: 1.8rem 0 10px;
  letter-spacing: -0.03em;
  display: flex;
  align-items: center;
  gap: 12px;
}
h2::before {
  content: "";
  width: 18px;
  height: 3px;
  background: var(--accent);
  flex: none;
}
h3 { font: 800 16px/1.3 var(--sans); margin: 1.2rem 0 8px; }
p, li { color: var(--muted); }
.teach p, .do p, .stuck p, main.page p { color: #d9d4c6; }
.teach, .do, .stuck, .bridge, .mastery { grid-column: 1; }
.rail { grid-column: 2; display: flex; flex-direction: column; gap: 16px; }

.stage {
  background: var(--mat);
  border: 1px solid var(--line);
  border-top: 2px solid var(--accent);
  border-radius: var(--hard);
  overflow: hidden;
  margin: 0 0 28px;
  box-shadow: 0 22px 48px rgba(0,0,0,.38);
}
main.lesson .stage {
  grid-column: 1 / -1;
}
.stage-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  grid-column: 1 / -1;
  margin: 0 0 28px;
}
.stage-pair .stage { margin: 0; }
.stage-pair .stage-mat { min-height: 280px; }
.stage-kicker {
  margin: 0 0 8px;
  color: var(--accent);
  font: 800 12px/1 var(--sans);
  letter-spacing: 0.12em;
}
.stage-mat { min-height: 380px; background: #101210; }
.stage-mat svg, .stage-mat canvas { display: block; width: 100%; height: auto; }
.stage.mini .stage-mat { min-height: 0; }
.stage.mini {
  margin: 0;
  border-radius: var(--hard);
  box-shadow: none;
  border-top-width: 2px;
}
.stage-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 10px 14px 12px;
  border-top: 1px solid var(--line);
  background: #121512;
}
.stage-beats {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 8px;
  align-items: center;
  padding: 10px 14px 0;
  background: #121512;
  border-top: 1px solid var(--line);
}
.stage-beats b {
  font: 800 11px/1 var(--sans);
  letter-spacing: 0.06em;
  color: #6b7266;
  padding: 6px 9px;
  border-radius: 2px;
  border: 1px solid transparent;
}
.stage-beats b.on {
  color: var(--accent-ink);
  background: var(--accent);
  border-color: var(--accent);
}
.stage-side {
  margin-left: auto;
  color: var(--muted);
  font: 700 12px/1.3 var(--sans);
}
.stage-cap {
  margin: 0;
  padding: 0 16px 14px;
  color: var(--ink);
  font-weight: 700;
  font-size: 15px;
  background: #121512;
}
.stage.mini .stage-bar, .stage.mini .stage-cap, .stage.mini .stage-beats { display: none; }
.spd { display: flex; align-items: center; gap: 8px; margin-left: auto; color: var(--muted); font-size: 13px; font-weight: 700; }
.spd input { width: 120px; accent-color: var(--accent); }

.ex, .fig, .card, .red, .okbox {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--hard);
  padding: 16px 18px;
}
.red {
  border-color: #4a221c;
  border-left: 6px solid var(--warn);
  background: #16100f;
}
.okbox { border-color: #3a4a16; border-left: 6px solid var(--accent); background: #151910; color: var(--ink); }
.ex {
  font: 15px/1.55 var(--sans);
  color: var(--ink);
  border-left: 4px solid var(--accent);
  background: #121512;
}
.ex ol { margin: 8px 0 0; padding-left: 1.2rem; }
.ex li { margin: 6px 0; color: var(--muted); }
.fig svg, .fig img { width: 100%; height: auto; display: block; }
.fig figcaption, .cap { margin-top: 10px; color: var(--muted); font-size: 14px; }

.path { list-style: none; padding: 0; margin: 0; }
.path li {
  display: grid;
  grid-template-columns: 3.4rem 1fr;
  gap: 16px;
  align-items: center;
  padding: 16px 0;
  border-top: 1px solid var(--line);
}
.path time {
  display: grid;
  place-items: center;
  width: 3.2rem;
  height: 3.2rem;
  color: var(--accent);
  font: 800 13px/1 var(--mono);
  border: 1px solid var(--accent);
  background: rgba(200,245,66,.06);
}
.path a { color: var(--ink); font-weight: 800; text-decoration: none; }
.path a:hover { color: var(--accent); }
.path small { display: block; color: var(--muted); font-weight: 400; margin-top: 4px; }

.choices { display: grid; gap: 8px; margin: 14px 0; }
.choices button, .act, .ghost {
  font: inherit;
  cursor: pointer;
  text-align: left;
  border-radius: var(--hard);
  font-weight: 800;
}
.choices button, .ghost {
  padding: 12px 14px;
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--ink);
}
.ghost.on, .choices button.is-ok { border-color: var(--accent); color: var(--accent); background: rgba(200,245,66,.06); }
.choices button.is-bad { border-color: var(--warn); color: var(--warn); }
.act {
  min-height: 46px;
  padding: 11px 18px;
  background: var(--accent);
  color: var(--accent-ink);
  border: 1px solid var(--accent);
  box-shadow: 4px 4px 0 #5c6d14;
}
.act:hover { transform: translate(-1px, -1px); box-shadow: 5px 5px 0 #5c6d14; }
.act:active { transform: translate(2px, 2px); box-shadow: 1px 1px 0 #5c6d14; }
a.act { display: inline-block; text-decoration: none; margin-top: 8px; }
.act.ok { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.out {
  margin: 10px 0;
  padding: 12px 14px;
  background: var(--panel);
  border-left: 4px solid var(--accent);
  border-radius: 0 var(--hard) var(--hard) 0;
  color: var(--ink);
}
.out.is-ok { border-color: var(--accent); }
.out.is-bad { border-color: var(--warn); }
label.block { display: grid; gap: 6px; margin: 12px 0; color: var(--ink); }
textarea, input[type="text"], input[type="search"] {
  font: inherit;
  padding: 10px 12px;
  border: 1px solid var(--line);
  background: #0e100e;
  color: var(--ink);
  border-radius: var(--hard);
}
.leave { margin: 2.2rem 0 0; color: var(--muted); grid-column: 1 / -1; }
.hero-links { display: flex; flex-wrap: wrap; align-items: center; gap: 18px 28px; margin: 24px 0 0; grid-column: 1 / -1; }
.hero-links a { font-weight: 800; text-decoration: none; }
.span { grid-column: 1 / -1; }
.two { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin: 16px 0; }

table { width: 100%; border-collapse: collapse; font-size: 15px; }
th, td { text-align: left; padding: 12px 8px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { font-size: 11px; letter-spacing: 0.12em; color: var(--muted); font-weight: 800; }

.board {
  display: grid;
  grid-template-columns: minmax(220px, 0.8fr) minmax(0, 1.1fr) minmax(260px, 0.8fr);
  gap: 18px;
  align-items: stretch;
  margin-top: 24px;
}
.timer-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 2px solid var(--accent);
  border-radius: var(--hard);
  padding: 28px 32px 24px;
  min-height: 380px;
  box-shadow: 0 22px 48px rgba(0,0,0,.32);
}
.now-name { margin: 0; font: 800 13px/1.3 var(--sans); color: var(--accent); letter-spacing: 0.16em; text-transform: uppercase; }
.now-big { margin: 12px 0 8px; font: 900 96px/0.9 var(--sans); letter-spacing: -0.07em; font-variant-numeric: tabular-nums; }
.now-meta { color: var(--muted); font: 15px/1.5 var(--mono); }
.now-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 24px; }
.cue-list { margin: 0; padding-left: 1.15rem; }
.cue-list li { margin: 8px 0; color: var(--ink); }
.log { font: 14px/1.5 var(--mono); color: var(--muted); white-space: pre-wrap; }
.queue { list-style: none; padding: 0; margin: 0; }
.queue li {
  display: flex;
  justify-content: space-between;
  padding: 8px 0;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}
.queue li.on { color: var(--accent); }
.queue li.done { text-decoration: line-through; opacity: 0.45; }

.dl { display: grid; grid-template-columns: 8rem 1fr; gap: 8px 16px; }
.dl dt { font-weight: 800; color: var(--ink); }
.dl dd { margin: 0; color: var(--muted); }

.foot {
  width: min(1180px, calc(100% - 80px));
  margin: 0 auto;
  padding: 0 0 40px;
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 13px;
}
.foot a { text-decoration: none; }

.home-hero { max-width: none; }
.home-split {
  display: grid;
  grid-template-columns: minmax(320px, 0.92fr) minmax(400px, 1.08fr);
  gap: 28px;
  align-items: center;
  margin-bottom: 18px;
}
.home-split .stage { margin: 0; }
.stat {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
  margin: 28px 0 8px;
}
.stat div {
  background: transparent;
  border: none;
  border-top: 2px solid var(--accent);
  border-radius: 0;
  padding: 14px 2px 10px;
}
.stat b { display: block; font: 900 32px/1 var(--sans); color: var(--accent); letter-spacing: -0.04em; }
.stat span { color: var(--muted); font-size: 12px; font-weight: 700; }

.move-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 12px;
  margin: 8px 0 28px;
  grid-column: 1 / -1;
}
.move-card {
  display: grid;
  gap: 8px;
  text-decoration: none;
  color: inherit;
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 2px solid #3a4228;
  border-radius: var(--hard);
  overflow: hidden;
}
.move-card:hover {
  border-top-color: var(--accent);
  border-color: #3a4a16;
  transform: translateY(-2px);
}
.move-card b { padding: 0 12px; color: var(--ink); font-size: 15px; }
.move-card span { padding: 0 12px 12px; color: var(--muted); font-size: 12px; font-weight: 700; }

@media (prefers-reduced-motion: reduce) {
  .stage-mat svg * { animation: none !important; }
  .act:hover, .move-card:hover { transform: none; }
}

@media (max-width: 1180px) {
  .move-grid { grid-template-columns: repeat(3, 1fr); }
  .board { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 900px) {
  main.lesson, .board, .home-split, .stage-pair { grid-template-columns: 1fr; }
  .rail { grid-column: 1; }
  h1 { font-size: 38px; }
  .now-big { font-size: 72px; }
  .stat, .move-grid { grid-template-columns: 1fr 1fr; }
}