:root {
  --primary: #0f766e;
  --primary-hover: #115e59;
  --accent: #14b8a6;
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #0f172a;
  --text-muted: #475569;
  --border: #e2e8f0;
  --radius: 8px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  color: var(--text);
  background-color: var(--bg);
  padding: 0;
  margin: 0;
}

header {
  background-color: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.nav-container {
  max-width: 860px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--primary);
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-muted);
  font-weight: 500;
  transition: color 0.15s ease-in-out;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
}

main {
  max-width: 860px;
  margin: 2rem auto;
  padding: 0 1.5rem 3rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2.5rem;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

h1 {
  font-size: 2rem;
  margin-bottom: 0.75rem;
  color: var(--text);
}

h2 {
  font-size: 1.35rem;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  color: var(--text);
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.35rem;
}

h3 {
  font-size: 1.1rem;
  margin-top: 1.25rem;
  margin-bottom: 0.5rem;
  color: var(--text);
}

p {
  margin-bottom: 1rem;
}

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

li {
  margin-bottom: 0.4rem;
}

a {
  color: var(--primary);
  text-decoration: underline;
}

a:hover {
  color: var(--primary-hover);
}

.hero {
  text-align: center;
  padding: 3rem 1rem;
}

.hero h1 {
  font-size: 2.5rem;
  color: var(--primary);
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.2rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto 2rem;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 1rem;
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius);
  font-weight: 600;
  text-decoration: none;
  transition: background-color 0.15s ease-in-out;
}

.btn-primary {
  background-color: var(--primary);
  color: #ffffff;
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  color: #ffffff;
}

.btn-secondary {
  background-color: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background-color: var(--bg);
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
  margin-top: 2.5rem;
}

.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.feature-card h3 {
  margin-top: 0;
  color: var(--primary);
}

footer {
  text-align: center;
  padding: 2rem 1.5rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  background-color: var(--surface);
}