:root { --signal: #f2827f; }
* { margin: 0; box-sizing: border-box; }
body {
  background: #fff;
  color: #222;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.6;
}
nav {
  display: flex;
  align-items: baseline;
  gap: 2rem;
  padding: 1.5rem 2rem;
}
nav .brand {
  color: var(--signal);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: 0.05em;
  text-decoration: none;
}
nav a { color: #555; text-decoration: none; }
nav a:hover { color: var(--signal); }

.hero {
  min-height: calc(100vh - 8rem);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.hero h1 {
  font-size: 4rem;
  color: var(--signal);
  letter-spacing: 0.05em;
}

main {
  max-width: 760px;
  margin: 0 auto;
  padding: 3rem 2rem;
}
main > h1 { font-size: 2.5rem; margin-bottom: 1.5rem; }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.5rem;
}
.card {
  display: block;
  padding: 1.5rem;
  border: 1px solid #eee;
  border-radius: 8px;
  text-decoration: none;
  color: inherit;
}
.card:hover { border-color: var(--signal); }
.card h3 { color: var(--signal); margin-bottom: 0.5rem; }
.card p { color: #555; font-size: 0.95rem; }

/* notebook rendering (notebookjs classes) */
.nb-notebook { line-height: 1.7; }
.nb-cell { margin-bottom: 1rem; }
.nb-markdown-cell h1 { color: var(--signal); font-size: 2.5rem; margin: 1rem 0; }
.nb-markdown-cell h2 { font-size: 1.5rem; margin: 2rem 0 0.75rem; }
.nb-markdown-cell p { margin-bottom: 1rem; }
.nb-markdown-cell img { max-width: 100%; border-radius: 8px; }
.nb-input pre {
  background: #fafafa;
  border: 1px solid #eee;
  border-left: 3px solid var(--signal);
  border-radius: 8px;
  padding: 1rem;
  overflow-x: auto;
  font-size: 0.9rem;
}
.nb-output pre {
  padding: 0.5rem 1rem;
  overflow-x: auto;
  font-size: 0.9rem;
  color: #555;
}
.nb-output img { max-width: 100%; }

.subscribe { max-width: 640px; margin: 3rem auto; padding: 0 1.5rem; text-align: center; }
.subscribe p { color: #555; font-size: 0.9rem; margin-bottom: 0.6rem; }
.subscribe input { padding: 0.5rem 0.75rem; border: 1px solid #ccc; border-radius: 6px; font-size: 0.9rem; min-width: 220px; }
.subscribe button { padding: 0.5rem 1rem; border: 1px solid var(--signal); background: var(--signal); color: #fff; border-radius: 6px; font-size: 0.9rem; cursor: pointer; margin-left: 0.4rem; }
.subscribe button:hover { opacity: 0.85; }

.hero .tagline { color: #888; font-size: 1rem; margin-top: 0.5rem; font-style: italic; }