:root {
  --bg: #ffffff;
  --surface: #f7f8fa;
  --fg: #0d1117;
  --muted: #6b7280;
  --accent: #2563eb;
  --accent-fg: #ffffff;
  --green: #16a34a;
  --green-bg: #ecfdf5;
  --green-border: #86efac;
  --yellow: #ca8a04;
  --yellow-bg: #fefce8;
  --yellow-border: #fde68a;
  --border: #d1d5db;
  --code-bg: #f3f4f6;
  --radius: 10px;
  --max-width: 720px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --surface: #161b22;
    --fg: #f3f4f6;
    --muted: #9ca3af;
    --accent: #3b82f6;
    --accent-fg: #ffffff;
    --green: #4ade80;
    --green-bg: #052e16;
    --green-border: #14532d;
    --yellow: #facc15;
    --yellow-bg: #422006;
    --yellow-border: #854d0e;
    --border: #30363d;
    --code-bg: #161b22;
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 20px;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 10;
  padding-top: calc(12px + env(safe-area-inset-top));
}

.topbar .brand {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
}

.topbar .brand:hover { color: var(--accent); }

.topbar .open-tg {
  background: var(--accent);
  color: var(--accent-fg);
  padding: 8px 14px;
  border-radius: 999px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 24px 20px calc(40px + env(safe-area-inset-bottom));
}

.hero {
  margin-bottom: 24px;
}

.hero h1 {
  font-size: 32px;
  letter-spacing: -0.5px;
  margin: 0 0 8px;
}

.hero .tagline {
  font-size: 16px;
  color: var(--muted);
  margin: 0;
}

.toc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 16px;
  margin-bottom: 24px;
  font-size: 14px;
}

.toc summary {
  cursor: pointer;
  font-weight: 600;
}

.toc ol {
  margin: 12px 0 0;
  padding-left: 20px;
}

.toc li { margin-bottom: 4px; }
.toc a { color: var(--accent); text-decoration: none; }
.toc a:hover { text-decoration: underline; }

section {
  margin-bottom: 32px;
}

h2 {
  font-size: 22px;
  margin: 0 0 12px;
  letter-spacing: -0.3px;
}

h3 {
  font-size: 16px;
  margin: 0 0 6px;
  color: var(--fg);
}

p { margin: 0 0 12px; }

ul, ol.steps {
  margin: 8px 0 16px;
  padding-left: 20px;
}

ol.steps { list-style: none; counter-reset: step; padding-left: 0; }
ol.steps li {
  counter-increment: step;
  position: relative;
  padding-left: 36px;
  margin-bottom: 14px;
}
ol.steps li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 24px;
  height: 24px;
  background: var(--accent);
  color: var(--accent-fg);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 700;
}

li { margin-bottom: 6px; }

a {
  color: var(--accent);
}

code {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
}

.callout {
  background: var(--surface);
  border-left: 3px solid var(--accent);
  border-radius: 0 8px 8px 0;
  padding: 12px 14px;
  margin: 16px 0;
  font-size: 14px;
}

.callout.ok { border-left-color: var(--green); background: var(--green-bg); }
.callout.warn { border-left-color: var(--yellow); background: var(--yellow-bg); }

.callout strong { color: var(--fg); }

.prompt {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  margin: 6px 0;
  font-size: 14px;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

.prompt::before {
  content: '💬 ';
  margin-right: 4px;
}

.prompt-inline {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 12px;
  margin: 12px 0;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
}

.card h3 { margin-bottom: 8px; }
.card p { font-size: 14px; color: var(--muted); margin-bottom: 10px; }
.card .prompt { margin-top: 10px; font-size: 13px; }

table {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0;
  font-size: 14px;
}

th, td {
  border: 1px solid var(--border);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}

th { background: var(--surface); font-weight: 600; }
td { background: var(--bg); }

details {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 14px;
  margin: 8px 0;
}

details summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 15px;
}

details[open] summary { margin-bottom: 8px; }
details p, details ul { font-size: 14px; color: var(--muted); }

footer {
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  font-size: 14px;
  color: var(--muted);
}

footer .meta {
  margin-top: 12px;
  font-size: 13px;
  text-align: center;
}

@media (max-width: 480px) {
  main { padding: 16px 14px 32px; }
  .hero h1 { font-size: 26px; }
  h2 { font-size: 19px; }
  .grid { grid-template-columns: 1fr; }
  .topbar .open-tg { padding: 6px 12px; font-size: 13px; }
}