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

:root {
  --bg: #fafafa;
  --text: #111;
  --muted: #555;
  --accent: #111;
  --border: #e0e0e0;
  --max-w: 720px;
}

html {
  font-size: 18px;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

/* --- Nav --- */

header {
  border-bottom: 1px solid var(--border);
}

nav {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 1.25rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.nav-contact {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.875rem;
}

.nav-contact:hover {
  color: var(--text);
}

/* --- Main --- */

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

/* --- Hero --- */

.hero {
  padding: 5rem 0 4rem;
}

.hero h1 {
  font-size: 2.4rem;
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.03em;
  max-width: 580px;
}

.hero-sub {
  margin-top: 1.25rem;
  font-size: 1.05rem;
  color: var(--muted);
  max-width: 540px;
  line-height: 1.7;
}

/* --- Features --- */

.features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  padding: 2rem 0 4rem;
  border-top: 1px solid var(--border);
}

.feature h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.feature p {
  font-size: 0.875rem;
  color: var(--muted);
  line-height: 1.6;
}

/* --- About --- */

.about {
  padding: 3rem 0;
  border-top: 1px solid var(--border);
}

.about h2 {
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
}

.about p {
  color: var(--muted);
  margin-bottom: 1rem;
  max-width: 600px;
}

/* --- CTA --- */

.cta {
  padding: 3rem 0 5rem;
  border-top: 1px solid var(--border);
}

.cta h2 {
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.cta p {
  color: var(--muted);
  margin-bottom: 1.5rem;
  max-width: 480px;
}

.btn {
  display: inline-block;
  padding: 0.7rem 1.5rem;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: 6px;
  transition: opacity 0.15s;
}

.btn:hover {
  opacity: 0.85;
}

/* --- Footer --- */

footer {
  border-top: 1px solid var(--border);
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

footer p {
  font-size: 0.8rem;
  color: var(--muted);
}

/* --- Responsive --- */

@media (max-width: 640px) {
  html {
    font-size: 16px;
  }

  .hero {
    padding: 3rem 0 2.5rem;
  }

  .hero h1 {
    font-size: 1.8rem;
  }

  .features {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
}