:root {
  --bg: #fafaf7;
  --surface: #ffffff;
  --ink: #1a1a1a;
  --ink-soft: #555;
  --ink-mute: #888;
  --accent: #2d6a4f;
  --line: #e8e6df;
  --radius: 10px;
  --max: 920px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body { line-height: 1.65; }

.container {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* header */
.site-header {
  border-bottom: 1px solid var(--line);
  padding: 1.25rem 0;
  background: var(--surface);
  position: sticky;
  top: 0;
  z-index: 10;
}
.site-header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.brand {
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: -0.01em;
}
nav a {
  color: var(--ink-soft);
  text-decoration: none;
  margin-left: 1.5rem;
  font-size: 0.95rem;
  transition: color 0.15s;
}
nav a:hover { color: var(--accent); }

/* hero */
.hero {
  padding: 5rem 0 4rem;
  border-bottom: 1px solid var(--line);
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
  max-width: 18ch;
}
.lede {
  font-size: 1.15rem;
  color: var(--ink-soft);
  max-width: 60ch;
}

/* sections */
section {
  padding: 4rem 0;
}
section + section {
  border-top: 1px solid var(--line);
}
h2 {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-bottom: 1.25rem;
}
p { margin-bottom: 1rem; color: var(--ink-soft); max-width: 65ch; }
p:last-child { margin-bottom: 0; }

/* topics grid */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.5rem;
}
.card h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--accent);
}
.card p {
  font-size: 0.95rem;
  margin-bottom: 0;
}

/* footer */
.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--line);
  padding: 3rem 0;
  margin-top: 2rem;
}
.footer-brand {
  font-weight: 700;
  font-size: 1rem;
  color: var(--ink);
  margin-bottom: 0.25rem;
  max-width: none;
}
.footer-note {
  color: var(--ink-soft);
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
}
.footer-legal {
  color: var(--ink-mute);
  font-size: 0.85rem;
  margin-bottom: 0;
}

/* small screens */
@media (max-width: 540px) {
  .hero { padding: 3rem 0; }
  nav a { margin-left: 1rem; }
  section { padding: 3rem 0; }
}