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

:root {
  --bg: #fff;
  --text: #111827;
  --muted: #6b7280;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --border: #e5e7eb;
  --radius: .5rem;
  --font: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

body { font-family: var(--font); color: var(--text); background: var(--bg); line-height: 1.6; }

/* ── nav ── */
header {
  border-bottom: 1px solid var(--border); padding: 1rem 2rem;
  position: sticky; top: 0; background: var(--bg); z-index: 10;
}
nav { max-width: 1100px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; }
.logo { font-weight: 700; font-size: 1.1rem; text-decoration: none; color: var(--text); }
nav a { color: var(--accent); text-decoration: none; font-size: .95rem; }
nav a:hover { text-decoration: underline; }

/* ── hero ── */
.hero { max-width: 680px; margin: 7rem auto; padding: 0 2rem; text-align: center; }
.hero h1 { font-size: 3.25rem; font-weight: 800; letter-spacing: -.03em; line-height: 1.1; margin-bottom: 1.25rem; }
.hero .tagline { font-size: 1.2rem; color: var(--muted); margin-bottom: 2rem; }
.cta { display: flex; gap: .75rem; justify-content: center; flex-wrap: wrap; }

.btn-primary, .btn-secondary {
  display: inline-block; padding: .65rem 1.4rem; border-radius: var(--radius);
  font-size: .95rem; font-weight: 500; text-decoration: none; transition: background .15s, color .15s, border-color .15s;
}
.btn-primary  { background: var(--accent); color: #fff; }
.btn-primary:hover  { background: var(--accent-hover); text-decoration: none; }
.btn-secondary { border: 1px solid var(--border); color: var(--text); }
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }

/* ── feature grid ── */
.features {
  max-width: 1100px; margin: 5rem auto; padding: 0 2rem;
  display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 1.5rem;
}
.feature { padding: 1.5rem; border: 1px solid var(--border); border-radius: var(--radius); }
.feature h3 { font-size: 1rem; font-weight: 600; margin-bottom: .5rem; }
.feature p  { font-size: .9rem; color: var(--muted); }

/* ── prose ── */
.content-body { max-width: 720px; margin: 4rem auto; padding: 0 2rem; }
.content-body h1, .content-body h2, .content-body h3 { margin-bottom: .75rem; }
.content-body h2 { font-size: 1.5rem; margin-top: 2rem; }
.content-body p  { color: var(--muted); margin-bottom: 1rem; }
.content-body code {
  background: #f3f4f6; padding: .1em .4em;
  border-radius: .25rem; font-size: .9em;
}

/* ── footer ── */
footer {
  text-align: center; padding: 2.5rem; color: var(--muted);
  font-size: .85rem; border-top: 1px solid var(--border); margin-top: 6rem;
}