:root {
  --bg: #0b0b0d;
  --panel: #131317;
  --panel-2: #1a1a20;
  --border: #26262e;
  --text: #ececf1;
  --muted: #8b8b98;
  --c-user: #ff8a3d;
  --c-agent: #b18cff;
  --c-iter: #4d9dff;
  --c-thinking: #8b8b98;
  --c-content: #ececf1;
  --c-tool: #3ddc97;
  --c-fork: #ff4fa3;
  --c-compact: #a3e635;
  --c-notify: #22d3ee;
  --c-activation: #fde047;
  --c-revert: #ef4444;
  --grad: linear-gradient(90deg, #ff8a3d, #ff4fa3 40%, #b18cff 70%, #4d9dff);
  --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  --sans: 'Inter', system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; }

html { background: var(--bg); color: var(--text); }
body {
  margin: 0;
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

main { max-width: 760px; margin: 0 auto; padding: 0 24px 120px; }

header.hero { padding: 96px 0 24px; }
.kicker {
  font-family: var(--mono); font-size: 12px; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--muted);
}
h1 {
  font-size: clamp(36px, 6vw, 56px); line-height: 1.05; letter-spacing: -0.03em;
  margin: 12px 0 20px; font-weight: 700;
}
h1 .grad { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
h2 {
  font-size: 28px; letter-spacing: -0.02em; margin: 88px 0 12px; line-height: 1.2;
}
h2 .num { font-family: var(--mono); font-size: 14px; color: var(--muted); display: block; margin-bottom: 6px; letter-spacing: 0.08em; }
p { color: #c9c9d2; margin: 0 0 18px; }
p strong { color: var(--text); }
a { color: var(--text); text-decoration-color: #ff4fa3; text-underline-offset: 3px; }
code, .m {
  font-family: var(--mono); font-size: 0.86em;
  background: var(--panel-2); border: 1px solid var(--border);
  padding: 1px 6px; border-radius: 5px; color: var(--text);
}
.lede { font-size: 19px; line-height: 1.6; color: #d6d6de; }
.source { font-family: var(--mono); font-size: 12.5px; line-height: 1.65; color: var(--muted); }
.source a { overflow-wrap: anywhere; }

/* token swatches inline in prose */
.t { font-family: var(--mono); font-size: 0.84em; font-weight: 600; white-space: nowrap; }

/* identifier chips (events, ACP calls, tools) — added by highlight() in lib.js */
.ident, code.ident, .mono.ident {
  --c: var(--text);
  font-family: var(--mono); font-size: 0.84em; font-weight: 600;
  color: var(--c); white-space: nowrap;
  background: color-mix(in srgb, var(--c) 13%, transparent);
  border: 1px solid color-mix(in srgb, var(--c) 30%, transparent);
  padding: 0 5px; border-radius: 4px;
}
.t::before { content: ''; display: inline-block; width: 8px; height: 8px; border-radius: 2px; margin-right: 6px; vertical-align: 1px; background: currentColor; }
.t-user { color: var(--c-user); } .t-agent { color: var(--c-agent); } .t-iter { color: var(--c-iter); }
.t-tool { color: var(--c-tool); } .t-fork { color: var(--c-fork); } .t-compact { color: var(--c-compact); }
.t-notify { color: var(--c-notify); } .t-activation { color: var(--c-activation); } .t-thinking { color: var(--c-thinking); }
.t-content { color: var(--c-content); } .t-revert { color: var(--c-revert); }

/* ---------- figures ---------- */
figure.viz {
  margin: 36px -80px 44px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 18px 18px 14px;
  position: relative;
}
@media (max-width: 920px) { figure.viz { margin-left: -12px; margin-right: -12px; } }

.viz-stage {
  background:
    radial-gradient(circle at 1px 1px, #1f1f26 1px, transparent 0) 0 0 / 22px 22px,
    var(--bg);
  border-radius: 10px;
  border: 1px solid var(--border);
  overflow: hidden;
}
.viz-stage svg { display: block; width: 100%; height: auto; }
.viz-stage svg text { font-family: var(--sans); }
.viz-stage svg .mono, .viz-stage svg text.mono { font-family: var(--mono); }

.viz-caption {
  min-height: 3.2em;
  font-size: 14.5px; line-height: 1.55; color: #d6d6de;
  padding: 12px 4px 4px;
}
.viz-caption code { font-size: 0.84em; font-weight: 600; }

.viz-controls {
  display: flex; flex-wrap: wrap; align-items: center; gap: 10px 16px;
  padding: 12px 0 2px; border-top: 1px dashed var(--border); margin-top: 8px;
}
.viz-transport, .viz-extra { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.viz-extra { order: 2; flex: 1 0 100%; }
.viz-extra:empty { display: none; }
.viz-btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  height: 32px; padding: 0 12px;
  font: 500 12.5px/1 var(--mono); white-space: nowrap;
  color: var(--text); background: var(--panel-2);
  border: 1px solid var(--border); border-radius: 8px;
  cursor: pointer;
  transition: border-color .15s, background .15s, color .15s, transform .05s;
}
.viz-btn-play { min-width: 92px; }
.viz-btn:hover:not(:disabled) { border-color: #3d3d48; background: #202028; }
.viz-btn:active:not(:disabled) { transform: translateY(1px); }
.viz-btn:focus-visible { outline: 2px solid var(--c-fork); outline-offset: 2px; }
.viz-btn-accent { border-color: #4a2a3d; color: #ffd0e6; }
.viz-btn-accent:hover:not(:disabled) { border-color: var(--c-fork); background: #24161e; }
.viz-btn:disabled {
  cursor: default; color: #5a5a66; background: transparent; border-color: #1f1f26;
}

.viz-speed {
  order: 1; margin-left: auto; display: flex; align-items: center; gap: 10px;
  height: 32px; font: 12px/1 var(--mono); color: var(--muted);
}
.viz-speed input { accent-color: #ff4fa3; width: 96px; margin: 0; }
.viz-speed input:focus-visible { outline: 2px solid var(--c-fork); outline-offset: 4px; border-radius: 4px; }
.viz-speed-val { min-width: 3.4em; text-align: right; color: var(--text); font-variant-numeric: tabular-nums; }

figure.viz figcaption {
  font-size: 13px; color: var(--muted); line-height: 1.55;
  margin-top: 12px; padding: 12px 4px 0; border-top: 1px solid var(--border);
}

.legend {
  display: flex; flex-wrap: wrap; align-items: center; gap: 8px 18px; margin: 20px 0 0;
  padding: 14px 18px; line-height: 1.5; border: 1px solid var(--border); border-radius: 12px; background: var(--panel);
}

footer { margin-top: 120px; padding-top: 24px; border-top: 1px solid var(--border); }

/* ---------- phone ---------- */
@media (max-width: 560px) {
  body { font-size: 16px; line-height: 1.65; }
  main { padding: 0 20px 96px; }
  header.hero { padding: 64px 0 16px; }
  .kicker { font-size: 11px; letter-spacing: 0.08em; }
  .lede { font-size: 17.5px; }
  h2 { font-size: 24px; margin-top: 72px; }
  figure.viz { margin: 28px -10px 36px; padding: 10px 10px 12px; border-radius: 14px; }
  .viz-stage { border-radius: 8px; }
  .viz-caption { font-size: 14px; padding: 10px 2px 2px; }
  .viz-controls { gap: 8px; }
  .viz-transport, .viz-extra { gap: 5px; }
  .viz-btn { padding: 0 9px; font-size: 12px; gap: 5px; }
  .viz-btn-play { min-width: 0; }
  .viz-speed { flex: 1 0 100%; margin-left: 0; }
  .viz-speed input { flex: 1; width: auto; }
  figure.viz figcaption { padding: 10px 2px 0; }
  .legend { padding: 12px 14px; gap: 6px 14px; }
}

/* ---------- per-figure Auto / Step-by-step switch ---------- */
.viz-mode {
  display: inline-flex; align-items: center; gap: 2px;
  padding: 2px; border-radius: 9px;
  background: var(--bg); border: 1px solid var(--border);
}
.viz-mode[hidden] { display: none; }
.viz-mode .viz-btn {
  height: 26px; padding: 0 10px; border: 1px solid transparent; border-radius: 7px;
  background: transparent; color: var(--muted);
}
.viz-mode .viz-btn:hover { color: var(--text); background: transparent; border-color: transparent; }
.viz-mode .viz-btn[aria-checked="true"] { color: #ffd0e6; background: #2a1622; border-color: #4a2a3d; }
.viz-btn.is-playing { color: var(--muted); border-style: dashed; }