:root {
  --bg: #ffffff;
  --bg-alt: #f8fafc;
  --text: #0f172a;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --green: #22c55e;
  --yellow: #facc15;
  --red: #ef4444;
  --max-width: 720px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --bg-alt: #1e293b;
    --text: #f1f5f9;
    --text-muted: #94a3b8;
    --border: #334155;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, sans-serif;
  font-size: 17px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

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

h1 {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  margin: 0 0 12px;
  line-height: 1.1;
}

h2 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.015em;
  margin: 2.5rem 0 1rem;
}

h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin: 1.5rem 0 0.5rem;
}

p { margin: 0 0 1rem; }

ul, ol { margin: 0 0 1rem; padding-left: 1.5rem; }
li { margin-bottom: 0.5rem; }

/* Hero (index) */
.hero-logo {
  width: 72px;
  height: 72px;
  border-radius: 16px;
  margin-bottom: 16px;
  display: block;
  margin-left: auto;
  margin-right: auto;
}

.hero {
  padding: 80px 0 60px;
  text-align: center;
  background: var(--bg-alt);
  border-bottom: 1px solid var(--border);
}

.hero h1 { font-size: 3rem; }

.tagline {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0 0 24px;
}

.lead {
  font-size: 1.125rem;
  color: var(--text-muted);
  margin: 0 auto 32px;
  max-width: 540px;
}

.cta { margin-top: 32px; }

.btn-primary {
  display: inline-block;
  padding: 14px 32px;
  background: var(--text);
  color: var(--bg);
  border-radius: 12px;
  font-weight: 600;
}

.btn-primary:hover {
  background: var(--text-muted);
  color: var(--bg);
  text-decoration: none;
}

/* Features */
.features { padding: 60px 0; }

.features.secondary {
  background: var(--bg-alt);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.features h2 { text-align: center; margin-top: 0; }

.feature-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin-top: 32px;
}

@media (min-width: 600px) {
  .feature-grid { grid-template-columns: repeat(3, 1fr); }
}

.feature {
  text-align: center;
  padding: 24px;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: var(--bg);
}

.dot {
  display: inline-block;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  margin-bottom: 12px;
}

.dot-green { background: var(--green); }
.dot-yellow { background: var(--yellow); }
.dot-red { background: var(--red); }

.feature h3 { margin: 0 0 8px; }

.feature p {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.feature-list {
  list-style: none;
  padding: 0;
  max-width: 540px;
  margin: 32px auto 0;
}

.feature-list li {
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
}

.feature-list li:last-child { border-bottom: none; }

/* Sub-page header */
.page-header {
  padding: 48px 0 24px;
  border-bottom: 1px solid var(--border);
}

.page-header h1 { font-size: 2rem; }

.breadcrumb {
  margin: 0 0 16px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.breadcrumb a { color: var(--text-muted); }

main { padding: 32px 0 64px; }

.prose h2 {
  border-top: 1px solid var(--border);
  padding-top: 1.5rem;
}

.prose h2:first-of-type {
  border-top: none;
  padding-top: 0;
}

/* FAQ */
details {
  margin: 0 0 12px;
  padding: 16px 20px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--bg-alt);
}

details[open] { background: var(--bg); }

summary {
  cursor: pointer;
  font-weight: 600;
  list-style: none;
}

summary::-webkit-details-marker { display: none; }

summary::after {
  content: "+";
  float: right;
  font-size: 1.25rem;
  color: var(--text-muted);
  font-weight: 400;
}

details[open] summary::after { content: "−"; }

details > p,
details > ul { margin-top: 12px; }

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding: 32px 0;
  background: var(--bg-alt);
  text-align: center;
}

footer p {
  margin: 0 0 8px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.copyright { font-size: 0.85rem; }

footer a { color: var(--text-muted); }

.updated-note {
  margin-top: 3rem;
  font-size: 0.9rem;
  color: var(--text-muted);
}