@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --ink: #EAE6D8;
    --ink-dim: #A9B0A6;
    --paper: #121C18;
    --panel: #1B2622;
    --panel-raised: #22302B;
    --line: #33453D;
    --signal: #59C4AC;
    --signal-dim: #2B453E;
    --amber: #F0A25E;
    --danger: #E08A6E;
    --danger-dim: #3B2A26;
    --shadow: rgba(0,0,0,0.4);
  }
}
:root[data-theme="dark"] {
  --ink: #EAE6D8;
  --ink-dim: #A9B0A6;
  --paper: #121C18;
  --panel: #1B2622;
  --panel-raised: #22302B;
  --line: #33453D;
  --signal: #59C4AC;
  --signal-dim: #2B453E;
  --amber: #F0A25E;
  --danger: #E08A6E;
  --danger-dim: #3B2A26;
  --shadow: rgba(0,0,0,0.4);
}
:root {
  --ink: #1B2320;
  --ink-dim: #5B6A61;
  --paper: #EDEAE0;
  --panel: #DFDACB;
  --panel-raised: #F2EFE5;
  --line: #B9B29A;
  --signal: #2F7A6B;
  --signal-dim: #C7D8CE;
  --amber: #C56A1E;
  --danger: #B34A2E;
  --danger-dim: #EAD3C9;
  --shadow: rgba(27,35,32,0.12);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--paper);
  color: var(--ink);
  font-family: -apple-system, "Segoe UI", system-ui, sans-serif;
  min-height: 100vh;
}
.mono { font-family: ui-monospace, "SF Mono", "Cascadia Code", Menlo, Consolas, monospace; }
.eyebrow {
  font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-dim);
}
h1, h2, h3 { text-wrap: balance; margin: 0; }

.shell { max-width: 1040px; margin: 0 auto; padding: 28px 24px 80px; }
header.console {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding: 14px 20px; border: 1px solid var(--line);
  border-radius: 10px; background: var(--panel); margin-bottom: 28px; flex-wrap: wrap;
}
.brand { display: flex; align-items: baseline; gap: 10px; }
.brand .mark { width: 10px; height: 10px; border-radius: 50%; background: var(--signal); box-shadow: 0 0 0 3px var(--signal-dim); flex: none; }
.brand .name { font-size: 1.05rem; font-weight: 700; letter-spacing: -0.01em; }
nav.switches { display: flex; gap: 6px; background: var(--paper); border: 1px solid var(--line); border-radius: 8px; padding: 3px; flex-wrap: wrap; }
nav.switches button {
  font: inherit; font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.72rem; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--ink-dim); background: transparent; border: none; border-radius: 6px;
  padding: 7px 12px; cursor: pointer;
}
nav.switches button.active { background: var(--signal); color: var(--paper); }
nav.switches button:focus-visible { outline: 2px solid var(--signal); outline-offset: 2px; }
.user-chip { font-family: ui-monospace, monospace; font-size: 0.72rem; color: var(--ink-dim); display: flex; align-items: center; gap: 10px; }
.user-chip button { font: inherit; background: transparent; border: 1px solid var(--line); color: var(--ink-dim); border-radius: 6px; padding: 6px 10px; cursor: pointer; }

.screen { display: none; }
.screen.active { display: block; }

/* ---- AUTH ---- */
.auth-wrap { max-width: 420px; margin: 60px auto; }
.auth-wrap .panel { padding: 28px; }
.auth-wrap h2 { font-size: 1.4rem; margin-bottom: 6px; }
.auth-wrap p.sub { color: var(--ink-dim); margin: 0 0 22px; font-size: 0.9rem; }
.field { margin-bottom: 14px; }
.field label { display: block; font-size: 0.75rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--ink-dim); margin-bottom: 6px; }
.field input {
  width: 100%; font: inherit; font-size: 0.94rem; color: var(--ink);
  background: var(--paper); border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px;
}
.field input:focus-visible { outline: 2px solid var(--signal); outline-offset: 1px; }
.auth-error {
  background: var(--danger-dim); border: 1px solid var(--danger); color: var(--danger);
  border-radius: 8px; padding: 10px 12px; font-size: 0.85rem; margin-bottom: 14px; display: none;
}
.auth-error.show { display: block; }
.auth-switch { margin-top: 16px; font-size: 0.85rem; color: var(--ink-dim); text-align: center; }
.auth-switch a { color: var(--signal); cursor: pointer; text-decoration: underline; }

/* ---- HOME ---- */
.hero { display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 40px; align-items: center; padding: 20px 4px 44px; border-bottom: 1px solid var(--line); margin-bottom: 36px; }
.hero h1 { font-size: clamp(2.1rem, 4vw, 2.9rem); line-height: 1.08; letter-spacing: -0.015em; }
.hero h1 em { font-style: normal; color: var(--signal); }
.hero p.lede { margin: 18px 0 0; max-width: 46ch; color: var(--ink-dim); font-size: 1.02rem; line-height: 1.6; }
.cta-row { display: flex; gap: 12px; margin-top: 26px; align-items: center; }
.btn { font: inherit; font-weight: 600; font-size: 0.92rem; padding: 12px 20px; border-radius: 8px; border: 1px solid transparent; cursor: pointer; }
.btn.primary { background: var(--signal); color: var(--paper); }
.btn.ghost { background: transparent; border-color: var(--line); color: var(--ink); }
.btn:disabled { opacity: 0.5; cursor: default; }
.hero-hint { font-size: 0.78rem; color: var(--ink-dim); }

.dial-wrap { display: flex; justify-content: center; }
.dial {
  width: 220px; height: 220px; border-radius: 50%; position: relative;
  background: radial-gradient(circle at 50% 50%, var(--panel-raised) 0 62%, transparent 63%),
    conic-gradient(from -120deg, var(--line) 0deg, var(--line) 240deg, transparent 240deg 360deg);
  border: 1px solid var(--line); box-shadow: inset 0 1px 0 var(--shadow);
}
.dial::after {
  content: ""; position: absolute; inset: 0; border-radius: 50%;
  background: conic-gradient(from -120deg, var(--signal) 0deg, var(--signal) var(--dial-deg, 0deg), transparent var(--dial-deg, 0deg) 360deg);
  -webkit-mask: radial-gradient(circle, transparent 61%, black 62%);
          mask: radial-gradient(circle, transparent 61%, black 62%);
}
.dial .readout { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 2px; }
.dial .readout .num { font-size: 2rem; font-weight: 700; font-family: ui-monospace, monospace; }
.dial .readout .label { font-size: 0.65rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--ink-dim); }

section.title-block { margin: 44px 0 18px; }
section.title-block .eyebrow { margin-bottom: 8px; }
section.title-block h2 { font-size: 1.5rem; }

.track-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; margin-top: 20px; margin-bottom: 44px; }
.track-card { border: 1px solid var(--line); background: var(--panel); border-radius: 12px; padding: 22px; display: flex; flex-direction: column; gap: 4px; }
.track-card .eyebrow { color: var(--signal); }
.track-card.track-card--safety .eyebrow { color: var(--amber); }
.track-card h3 { font-size: 1.15rem; margin: 6px 0 2px; }
.track-card p { margin: 0 0 14px; font-size: 0.92rem; color: var(--ink-dim); line-height: 1.5; }
.track-progress { height: 6px; border-radius: 3px; background: var(--line); overflow: hidden; margin-bottom: 6px; }
.track-progress-fill { height: 100%; background: var(--signal); border-radius: 3px; }
.track-card--safety .track-progress-fill { background: var(--amber); }
.track-progress-label { font-size: 0.75rem; color: var(--ink-dim); margin-bottom: 14px; }
.track-card .btn { align-self: flex-start; }

.why-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 20px; }
.why-card { border: 1px solid var(--line); background: var(--panel); border-radius: 10px; padding: 18px; }
.why-card .idx { font-family: ui-monospace, monospace; font-size: 0.72rem; color: var(--signal); }
.why-card h3 { font-size: 1rem; margin: 8px 0 6px; }
.why-card p { margin: 0; font-size: 0.88rem; color: var(--ink-dim); line-height: 1.5; }

/* ---- LEVEL MAP ---- */
.map-head { margin-bottom: 26px; }
.map-head p { color: var(--ink-dim); max-width: 56ch; line-height: 1.6; margin: 8px 0 0; }
.path { position: relative; padding-left: 34px; }
.path::before { content: ""; position: absolute; left: 10px; top: 10px; bottom: 10px; width: 2px; background: repeating-linear-gradient(to bottom, var(--line) 0 6px, transparent 6px 12px); }
.node {
  position: relative; display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 18px;
  padding: 18px 20px; border: 1px solid var(--line); background: var(--panel); border-radius: 10px; margin-bottom: 14px; cursor: pointer;
}
.node::before { content: ""; position: absolute; left: -30px; top: 50%; transform: translateY(-50%); width: 12px; height: 12px; border-radius: 50%; background: var(--paper); border: 2px solid var(--line); }
.node.done::before { background: var(--signal); border-color: var(--signal); }
.node.active::before { background: var(--paper); border-color: var(--signal); box-shadow: 0 0 0 3px var(--signal-dim); }
.node .chnum { font-family: ui-monospace, monospace; font-size: 0.75rem; color: var(--ink-dim); width: 46px; }
.node.active .chnum, .node.done .chnum { color: var(--signal); }
.node h3 { font-size: 1.02rem; margin-bottom: 4px; }
.node p { margin: 0; font-size: 0.84rem; color: var(--ink-dim); }
.node .status { font-family: ui-monospace, monospace; font-size: 0.68rem; letter-spacing: 0.08em; text-transform: uppercase; padding: 6px 10px; border-radius: 6px; white-space: nowrap; }
.node.done .status { background: var(--signal-dim); color: var(--signal); }
.node.active .status { background: var(--amber); color: var(--paper); }
.node.locked .status, .node.coming_soon .status { background: transparent; color: var(--ink-dim); border: 1px solid var(--line); }
.node.locked, .node.coming_soon { opacity: 0.55; cursor: default; }

/* ---- CHALLENGE ---- */
.challenge-head { display: flex; justify-content: space-between; align-items: flex-end; gap: 20px; margin-bottom: 22px; flex-wrap: wrap; }
.challenge-head h2 { font-size: 1.4rem; }
.challenge-head .eyebrow { margin-bottom: 6px; }
.console-grid { display: grid; grid-template-columns: 1.3fr 0.9fr; gap: 20px; }
.panel { border: 1px solid var(--line); background: var(--panel); border-radius: 12px; padding: 22px; }
.panel h3 { font-size: 0.78rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-dim); margin-bottom: 14px; }
.scenario-box { background: var(--panel-raised); border: 1px solid var(--line); border-radius: 8px; padding: 16px; font-size: 0.94rem; line-height: 1.6; margin-bottom: 18px; }
.prompt-noisy { font-family: ui-monospace, monospace; font-size: 0.85rem; color: var(--ink-dim); padding: 12px 14px; border: 1px dashed var(--line); border-radius: 6px; margin-bottom: 18px; }
textarea.rewrite {
  width: 100%; min-height: 90px; resize: vertical; font: inherit; font-size: 0.92rem; color: var(--ink);
  background: var(--paper); border: 1px solid var(--line); border-radius: 8px; padding: 12px;
}
textarea.rewrite:focus-visible { outline: 2px solid var(--signal); outline-offset: 1px; }
.submit-row { display: flex; justify-content: space-between; align-items: center; margin-top: 14px; }
.scenario-picker { display: flex; gap: 6px; margin-bottom: 16px; }
.scenario-picker button {
  font: inherit; font-family: ui-monospace, monospace; font-size: 0.7rem; padding: 6px 10px;
  border-radius: 6px; border: 1px solid var(--line); background: transparent; color: var(--ink-dim); cursor: pointer;
}
.scenario-picker button.active { background: var(--signal); color: var(--paper); border-color: var(--signal); }

.meter { display: flex; flex-direction: column; align-items: center; padding: 10px 0 6px; }
.meter-arc { width: 160px; height: 90px; position: relative; overflow: hidden; }
.meter-arc .track { width: 160px; height: 160px; border-radius: 50%; border: 14px solid var(--line); box-sizing: border-box; }
.meter-arc .fill {
  position: absolute; inset: 0; width: 160px; height: 160px; border-radius: 50%; border: 14px solid var(--signal); box-sizing: border-box;
  clip-path: polygon(0 0, var(--meter-x, 0%) 0, var(--meter-x, 0%) 100%, 0 100%);
}
.meter .readnum { font-family: ui-monospace, monospace; font-size: 1.6rem; font-weight: 700; margin-top: -46px; }
.meter .readlabel { font-size: 0.68rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-dim); margin-top: 2px; }

.feedback { margin-top: 18px; padding: 14px 16px; border-radius: 8px; background: var(--signal-dim); border: 1px solid var(--signal); font-size: 0.86rem; line-height: 1.55; }
.feedback strong { color: var(--signal); display: block; font-family: ui-monospace, monospace; font-size: 0.7rem; letter-spacing: 0.08em; text-transform: uppercase; margin-bottom: 6px; }
.feedback.empty { background: var(--panel-raised); border-color: var(--line); color: var(--ink-dim); }
.feedback.empty strong { color: var(--ink-dim); }

.criteria-list { list-style: none; margin: 12px 0 0; padding: 0; font-size: 0.82rem; }
.criteria-list li { padding: 4px 0; color: var(--ink-dim); }
.criteria-list li.met { color: var(--signal); }
.criteria-list li::before { content: "○ "; }
.criteria-list li.met::before { content: "● "; }

.stat-row { display: flex; gap: 10px; margin-top: 18px; }
.stat-chip { flex: 1; text-align: center; padding: 10px 6px; border: 1px solid var(--line); border-radius: 8px; background: var(--panel-raised); }
.stat-chip .v { font-family: ui-monospace, monospace; font-weight: 700; font-size: 1.05rem; }
.stat-chip .l { font-size: 0.65rem; color: var(--ink-dim); text-transform: uppercase; letter-spacing: 0.06em; margin-top: 2px; }

/* ---- LEADERBOARD ---- */
.lb-head { margin-bottom: 22px; }
.lb-head p { color: var(--ink-dim); margin: 8px 0 0; }
.lb-list { list-style: none; margin: 0; padding: 0; }
.lb-row {
  display: grid; grid-template-columns: 40px 1fr auto auto; align-items: center; gap: 14px;
  padding: 14px 18px; border: 1px solid var(--line); background: var(--panel); border-radius: 10px; margin-bottom: 10px;
}
.lb-row .rank { font-family: ui-monospace, monospace; font-size: 0.85rem; color: var(--ink-dim); }
.lb-row.top .rank { color: var(--signal); font-weight: 700; }
.lb-row .name { font-weight: 600; }

.msg-empty { color: var(--ink-dim); font-size: 0.9rem; padding: 20px 0; }

@media (max-width: 720px) {
  .hero { grid-template-columns: 1fr; }
  .dial-wrap { order: -1; }
  .why-grid { grid-template-columns: 1fr; }
  .track-grid { grid-template-columns: 1fr; }
  .console-grid { grid-template-columns: 1fr; }
  .node { grid-template-columns: auto 1fr; }
  .node .status { grid-column: 2; justify-self: start; margin-top: 6px; }
  .lb-row { grid-template-columns: 30px 1fr auto; }
  .lb-row .cleared { display: none; }
}