body {
  font-family: system-ui, sans-serif;
  margin: 0;
  padding: 0;
  line-height: 1.6;
  color: #111;
  background: #fafafa;
}

header {
  border-bottom: 1px solid #ddd;
  background: #fff;
}

nav {
  display: flex;
  gap: 1.5rem;
  padding: 1rem 2rem;
  align-items: center;
}

.logo {
  font-weight: 600;
  margin-right: auto;
}

nav a {
  text-decoration: none;
  color: #111;
}

nav a.cta {
  border: 1px solid #111;
  padding: 0.4rem 0.8rem;
}

main {
  max-width: 1500px;
  margin: 3rem auto;
  padding: 0 2rem;
}

section {
  margin-bottom: 1rem;
  max-width: 1500px;
  padding-top: 0.5rem;
}

section ul ul > li {
  margin-bottom: 0.5rem;
}

section > ul > li {
  margin-bottom: 0.5rem;
}

h1, h2 {
  font-weight: 600;
}

.tagline {
  font-size: 1.1rem;
  color: #333;
}

ul {
  padding-left: 1.2rem;
}

.muted {
  color: #777;
}

.note {
  font-size: 0.9rem;
  color: #555;
}

footer {
  border-top: 1px solid #ddd;
  padding: 1rem 2rem;
  font-size: 0.85rem;
  color: #555;
  background: #fff;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}

.card {
  border: 1px solid #ddd;
  background: #fff;
  padding: 1.5rem;
}

.card h3 {
  margin-top: 0;
}

.card-subtitle {
  font-size: 0.9rem;
  color: #555;
  margin-bottom: 1rem;
}

.price {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.price span {
  font-size: 1.6rem;
}

.price.secondary {
  font-size: 0.95rem;
  color: #555;
  margin-bottom: 1rem;
}

.card-list {
  padding-left: 1.2rem;
  margin: 1rem 0;
}

.card-note {
  font-size: 0.85rem;
  color: #555;
}

.card.muted {
  color: #777;
  background: #f6f6f6;
}

.card.muted .price {
  color: #777;
}

.cta-block {
  margin: 3rem 0;
  text-align: center;
}

.cta-large {
  display: inline-block;
  border: 1px solid #111;
  padding: 0.6rem 1.2rem;
  text-decoration: none;
  color: #111;
  font-weight: 600;
}

pre {
  background: #f6f6f6;
  padding: 0.75rem;
  border-left: 3px solid #ccc;
  font-size: 0.9rem;
  color: #000;
}

.example-block {
  margin: 2.5rem 0;
  padding: 1.25rem 1.5rem;
  background: #f6f6f6;
  border-left: 4px solid #ccc;
  font-size: 0.95rem;
}

.example-block p {
  margin: 0.6rem 0;
}

.example-label {
  font-weight: 600;
  font-size: 0.85rem;
  color: #555;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

/* ============================
   Invariant Pack Layout
   ============================ */

.pack-section {
  margin-bottom: 4rem;
}

.pack-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.5rem;
}

.pack {
  border: 1px solid #ddd;
  background: #fff;
  padding: 1.25rem 1.5rem;
}

.pack h3 {
  margin-top: 0;
  margin-bottom: 0.75rem;
  font-size: 1.05rem;
}

.pack ul {
  margin: 0;
  padding-left: 1.2rem;
}

/* ============================
   Function signature wrapping
   ============================ */

.pack code {
  display: block;
  white-space: pre-line;
}

/* ============================
   Domain flow layout (final)
   ============================ */

.domain-grid {
  column-count: 4;
  column-gap: 1.5rem;
}

.domain {
  break-inside: avoid;
  margin-bottom: 1.5rem;
}

.domain h3 {
  margin-top: 0;
  margin-bottom: 0.5rem;
  font-size: 1rem;
}

@media (max-width: 900px) {
  .domain-grid {
    column-count: 2;
  }
}

@media (max-width: 600px) {
  .domain-grid {
    column-count: 1;
  }
}