:root {
  --bg: #f7f7f9;
  --panel: #ffffff;
  --ink: #1b1b21;
  --muted: #62626d;
  --line: #e3e3ea;
  --line-strong: #cfcfda;
  --accent: #2f6feb;
  --accent-soft: #eaf0fe;
  --ok: #1a7f37;
  --ok-soft: #e6f4ea;
  --bad: #cf222e;
  --bad-soft: #fdecee;
  --warn: #8a6100;
  --warn-soft: #fff4d6;
  --code-bg: #f4f4f7;
  --term-bg: #14161b;
  --term-ink: #dfe3ea;
  --term-dim: #8b93a1;
  --term-ok: #57d38c;
  --term-accent: #7fb0ff;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(20, 22, 27, 0.05), 0 8px 24px rgba(20, 22, 27, 0.05);
  --sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Noto Sans SC", "PingFang SC", sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0e1014;
    --panel: #15181e;
    --ink: #e8e8ef;
    --muted: #a0a6b2;
    --line: #252a33;
    --line-strong: #333947;
    --accent: #6aa1ff;
    --accent-soft: #17233b;
    --ok: #4ac26b;
    --ok-soft: #14261a;
    --bad: #ff6b6b;
    --bad-soft: #2a1618;
    --warn: #d4a72c;
    --warn-soft: #2a2312;
    --code-bg: #1b1f27;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 10px 30px rgba(0, 0, 0, 0.25);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

code, pre, .mono { font-family: var(--mono); }

.top {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px clamp(16px, 4vw, 40px);
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.brand {
  font-family: var(--mono);
  font-size: 15px;
  letter-spacing: 0.02em;
  color: var(--ink);
  font-weight: 600;
  white-space: nowrap;
}

.top nav { display: flex; align-items: center; gap: 18px; font-size: 14px; }
.top nav a { color: var(--muted); }
.top nav a:hover { color: var(--ink); text-decoration: none; }

.lang {
  border: 1px solid var(--line-strong);
  background: transparent;
  color: var(--ink);
  border-radius: 999px;
  padding: 4px 12px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  white-space: nowrap;
}
.lang:hover { border-color: var(--accent); color: var(--accent); }

main { padding: 0 clamp(16px, 4vw, 40px); }

.hero { max-width: 1100px; margin: 0 auto; padding: clamp(48px, 9vw, 104px) 0 32px; }
.kicker {
  margin: 0 0 14px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.hero h1 {
  margin: 0;
  max-width: 20ch;
  font-size: clamp(2rem, 5.4vw, 3.5rem);
  line-height: 1.1;
  letter-spacing: -0.02em;
}
.lede {
  margin: 20px 0 0;
  max-width: 62ch;
  font-size: clamp(1rem, 1.6vw, 1.15rem);
  color: var(--muted);
}
.sim { margin: 18px 0 0; font-size: 13px; color: var(--muted); }

.actors {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 14px;
  margin-top: 38px;
}
.actor {
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: var(--radius);
  padding: 18px;
}
.actor h3 { margin: 0 0 4px; font-size: 15px; }
.actor ul { margin: 10px 0 0; padding-left: 18px; color: var(--muted); font-size: 14px; }
.actor li { margin: 3px 0; }
.actor .tag {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}
.actor.github-side { border-top: 3px solid var(--accent); }
.actor.operator-side { border-top: 3px solid var(--ok); }
.actor.target-side { border-top: 3px solid var(--warn); }
.actor .flow { margin-top: 12px; font-size: 12px; color: var(--muted); font-family: var(--mono); }

.limits {
  max-width: 1100px;
  margin: 0 auto;
  padding-top: 12px;
}
.limit-list {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
}
.limit {
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: var(--radius);
  padding: 14px 16px;
}
.limit strong { display: block; font-size: 14px; margin-bottom: 4px; }
.limit p { margin: 0; color: var(--muted); font-size: 13.5px; }

.faq { max-width: 1100px; margin: 0 auto; padding: clamp(40px, 7vw, 76px) 0 0; }
.faq-list { margin-top: 22px; max-width: 78ch; border-top: 1px solid var(--line); }
.faq-item { border-bottom: 1px solid var(--line); padding: 2px 0; }
.faq-item summary {
  cursor: pointer;
  padding: 14px 2px;
  font-size: 15.5px;
  font-weight: 550;
  list-style: none;
  display: flex;
  gap: 10px;
  align-items: baseline;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::before {
  content: "+";
  color: var(--muted);
  font-family: var(--mono);
  width: 12px;
  flex: none;
}
.faq-item[open] summary::before { content: "−"; color: var(--accent); }
.faq-item[open] summary { color: var(--accent); }
.faq-item p { margin: 0 0 16px 22px; color: var(--muted); font-size: 14px; }

.tour, .variants, .states, .adopt {
  max-width: 1100px;
  margin: 0 auto;
  padding: clamp(40px, 7vw, 76px) 0 0;
}
.section-head h2 { margin: 0; font-size: clamp(1.4rem, 3vw, 2rem); letter-spacing: -0.01em; }
.section-head p { margin: 8px 0 0; max-width: 66ch; color: var(--muted); }

.tabs { display: flex; flex-wrap: wrap; gap: 8px; margin: 26px 0 8px; }
.tab {
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--muted);
  border-radius: 999px;
  padding: 7px 14px;
  font: inherit;
  font-size: 14px;
  cursor: pointer;
}
.tab:hover { border-color: var(--line-strong); color: var(--ink); }
.tab[aria-selected="true"] {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 600;
}

.stepper { display: flex; flex-wrap: wrap; gap: 6px; margin: 14px 0 14px; }
.step-dot {
  border: 0;
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-size: 13px;
  padding: 6px 10px;
  border-radius: 8px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 7px;
}
.step-dot:hover { background: var(--panel); color: var(--ink); }
.step-dot[aria-selected="true"] { background: var(--panel); color: var(--ink); box-shadow: var(--shadow); }
.step-dot .n {
  display: inline-grid;
  place-items: center;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 1px solid var(--line-strong);
  font-size: 11px;
  font-family: var(--mono);
}
.step-dot[aria-selected="true"] .n { background: var(--accent); border-color: var(--accent); color: #fff; }

.progress { height: 3px; background: var(--line); border-radius: 999px; overflow: hidden; margin-bottom: 20px; }
.progress span { display: block; height: 100%; width: 0; background: var(--accent); transition: width 240ms ease; }

.stage {
  display: grid;
  grid-template-columns: 1.08fr 0.92fr;
  gap: 16px;
  align-items: stretch;
}
.pane {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  overflow: hidden;
  min-height: 430px;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow);
}
.pane-head {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  font-size: 12px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--muted);
}
.pane-head .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); }
.pane.machine { background: var(--term-bg); border-color: #22262e; color: var(--term-ink); }
.pane.machine .pane-head { border-color: #22262e; color: var(--term-dim); }
.pane.machine .pane-head .dot { background: var(--term-ok); }
.pane-body { padding: 16px; overflow: auto; flex: 1; }
.pane.machine .pane-body { padding: 16px; }

.swap { animation: fade 220ms ease; }
@keyframes fade { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

/* GitHub mock blocks */
.event {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--muted);
  border: 1px solid var(--line);
  background: var(--bg);
  border-radius: 999px;
  padding: 4px 10px;
  margin-bottom: 14px;
  font-family: var(--mono);
}
.pr-title { font-size: 16px; font-weight: 600; margin: 0 0 2px; }
.pr-meta { font-size: 13px; color: var(--muted); margin: 0 0 14px; }
.files { display: flex; flex-direction: column; gap: 6px; margin: 0 0 14px; }
.file {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  font-family: var(--mono);
  font-size: 12.5px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 7px 10px;
  background: var(--bg);
}
.file .stat { display: flex; gap: 7px; }
.file .add { color: var(--ok); }
.file .del { color: var(--bad); }

.kv {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 5px 14px;
  margin: 14px 0 4px;
  font-size: 13px;
}
.kv dt { font-family: var(--mono); color: var(--accent); white-space: nowrap; }
.kv dd { margin: 0; color: var(--muted); }

.checks { display: flex; flex-direction: column; gap: 6px; margin: 6px 0 14px; }
.check {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 13.5px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 8px 10px;
}
.check .state { margin-left: auto; font-size: 12px; color: var(--muted); }
.check .ind {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex: none;
  background: var(--line-strong);
}
.check.ok .ind { background: var(--ok); }
.check.ok .state { color: var(--ok); }
.check.bad .ind { background: var(--bad); }
.check.bad .state { color: var(--bad); }
.check.pending .ind { background: var(--warn); }
.check.pending .state { color: var(--warn); }
.check.missing .ind { border: 1px dashed var(--line-strong); background: transparent; }

.comment {
  border: 1px solid var(--line);
  border-radius: 10px;
  overflow: hidden;
  margin: 8px 0 14px;
}
.comment-head {
  display: flex;
  gap: 8px;
  align-items: baseline;
  padding: 8px 12px;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
  font-size: 12.5px;
  color: var(--muted);
}
.comment-head strong { color: var(--ink); font-weight: 600; }
.comment-body { padding: 10px 12px; }
.comment-body pre { margin: 0; }

pre.code {
  margin: 0;
  padding: 12px 14px;
  background: var(--code-bg);
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: auto;
  font-size: 12.2px;
  line-height: 1.55;
}
pre.code.small { font-size: 11.4px; }
code.inline {
  background: var(--code-bg);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 1px 5px;
  font-size: 0.9em;
}

.note {
  border-left: 3px solid var(--line-strong);
  padding: 2px 0 2px 12px;
  color: var(--muted);
  font-size: 14px;
  margin: 12px 0 0;
}
.note.accent { border-color: var(--accent); color: var(--ink); }
.note.ok { border-color: var(--ok); }

.jobs { display: flex; flex-direction: column; gap: 6px; margin: 8px 0 12px; }
.job { display: flex; gap: 9px; align-items: center; font-size: 13px; }
.job .ind { width: 8px; height: 8px; border-radius: 50%; background: var(--ok); flex: none; }
.job .time { margin-left: auto; color: var(--muted); font-size: 12px; font-family: var(--mono); }

.summary {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 12px 14px;
  background: var(--bg);
  margin: 10px 0 0;
}
.summary h4 { margin: 0 0 8px; font-size: 13.5px; }
.summary pre { margin: 0; font-size: 12px; color: var(--muted); white-space: pre-wrap; }
.summary details { margin-top: 8px; }
.summary summary { cursor: pointer; color: var(--accent); font-size: 13px; }

/* machine pane blocks */
.term-title { color: var(--term-dim); font-size: 12px; margin: 0 0 10px; letter-spacing: 0.04em; text-transform: uppercase; }
.term { font-family: var(--mono); font-size: 12.8px; line-height: 1.7; white-space: pre-wrap; word-break: break-word; }
.term .cmd { color: var(--term-ink); }
.term .out { color: var(--term-dim); }
.term .ok { color: var(--term-ok); }
.term .file { color: var(--term-accent); border: 0; background: transparent; padding: 0; display: inline; }

.receipt {
  margin-top: 14px;
  border: 1px solid #2a2f39;
  border-radius: 10px;
  background: #0f1115;
  overflow: hidden;
}
.receipt-head {
  padding: 8px 12px;
  border-bottom: 1px solid #22262e;
  color: var(--term-dim);
  font-size: 12px;
  display: flex;
  gap: 8px;
  align-items: center;
}
.receipt pre {
  margin: 0;
  padding: 12px;
  overflow: auto;
  font-size: 11.2px;
  line-height: 1.55;
  color: #cfd6e2;
  max-height: 220px;
}
.chips { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 12px; }
.chip {
  font-size: 11.5px;
  border: 1px solid #2a2f39;
  color: var(--term-dim);
  border-radius: 999px;
  padding: 3px 9px;
  font-family: var(--mono);
}
.chip.ok { color: var(--term-ok); border-color: #244a33; }

.checklist {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  font-size: 13px;
  color: var(--term-dim);
}
.checklist li { display: flex; gap: 8px; padding: 2px 0; }
.checklist .tick { color: var(--term-ok); }

.machine .note { color: var(--term-dim); border-color: #2a2f39; }
.machine .note.accent { color: var(--term-ink); border-color: var(--term-accent); }

.caption { margin: 20px 0 0; max-width: 78ch; }
.caption h3 { margin: 0 0 6px; font-size: clamp(1.1rem, 2.2vw, 1.4rem); }
.caption p { margin: 0; color: var(--muted); }
.caption code { color: var(--ink); }

.controls { display: flex; align-items: center; gap: 14px; margin: 22px 0 0; }
.btn {
  border: 1px solid var(--line-strong);
  background: var(--panel);
  color: var(--ink);
  border-radius: 8px;
  padding: 8px 16px;
  font: inherit;
  font-size: 14px;
  cursor: pointer;
}
.btn:hover:not(:disabled) { border-color: var(--accent); color: var(--accent); }
.btn:disabled { opacity: 0.4; cursor: default; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover:not(:disabled) { filter: brightness(1.08); color: #fff; }
.counter { color: var(--muted); font-size: 13px; font-family: var(--mono); }

.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 26px; }
.card {
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: var(--radius);
  padding: 18px;
  display: flex;
  flex-direction: column;
}
.card h3 { margin: 0 0 6px; font-size: 15.5px; }
.card p { margin: 0; color: var(--muted); font-size: 14px; flex: 1; }
.card a { margin-top: 14px; font-size: 13.5px; }

.state-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 26px; }
.state-card {
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: var(--radius);
  padding: 16px;
  border-top-width: 3px;
}
.state-card h3 { margin: 0 0 4px; font-family: var(--mono); font-size: 14px; }
.state-card p { margin: 0; color: var(--muted); font-size: 13.5px; }
.state-card.verified { border-top-color: var(--ok); }
.state-card.failed { border-top-color: var(--bad); }
.state-card.unverified { border-top-color: var(--warn); }
.state-card.na { border-top-color: var(--line-strong); }

.adopt-list {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  counter-reset: adopt;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}
.adopt-list li {
  counter-increment: adopt;
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: var(--radius);
  padding: 16px 16px 16px 52px;
  position: relative;
  font-size: 14px;
  color: var(--muted);
}
.adopt-list li::before {
  content: counter(adopt);
  position: absolute;
  left: 16px;
  top: 15px;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent);
  display: grid;
  place-items: center;
  font-size: 12px;
  font-family: var(--mono);
}
.adopt-list strong { color: var(--ink); display: block; margin-bottom: 3px; }
.adopt-note { margin: 14px 0 0; max-width: 70ch; color: var(--muted); font-size: 14px; }

footer {
  max-width: 1100px;
  margin: 72px auto 0;
  padding: 22px 0 40px;
  border-top: 1px solid var(--line);
  display: flex;
  gap: 18px;
  font-size: 13px;
  color: var(--muted);
}
footer span { font-family: var(--mono); color: var(--ink); }

.noscript { max-width: 60ch; margin: 40px auto; padding: 0 16px; }

@media (max-width: 920px) {
  .actors, .cards, .state-grid, .limit-list { grid-template-columns: 1fr 1fr; }
  .stage { grid-template-columns: 1fr; }
  .pane { min-height: 340px; }
  .adopt-list { grid-template-columns: 1fr; }
}

@media (max-width: 620px) {
  .actors, .cards, .state-grid, .limit-list { grid-template-columns: 1fr; }
  .top { gap: 10px; }
  .top nav { gap: 10px; }
  .top nav a[href="#states"],
  .top nav a[href="#scenarios"],
  .top nav a[href="#faq"] { display: none; }
  .brand { font-size: 14px; }
  .step-dot span.lbl { display: none; }
  .step-dot { padding: 4px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation: none !important; transition: none !important; }
}