:root {
  --bg: #1a1410;
  --card: #241b15;
  --accent: #c7372f;
  --accent-2: #f4a261;
  --text: #f1e8e0;
  --muted: #a89a8e;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}
a { color: var(--accent-2); }
a:hover { color: var(--accent); }

header.site {
  background: linear-gradient(135deg, #2a1612 0%, #4a1f1a 100%);
  padding: 4rem 1.5rem 3rem;
  text-align: center;
  border-bottom: 3px solid var(--accent);
}
header.site h1 {
  margin: 0 0 0.5rem;
  font-size: clamp(2rem, 5vw, 3.5rem);
  color: var(--accent-2);
}
header.site p {
  margin: 0 auto;
  color: var(--muted);
  font-size: 1.1rem;
  max-width: 640px;
}
.raspberry { font-size: 3rem; display: block; margin-bottom: 0.5rem; }

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 3rem 1.5rem;
}

h2 {
  color: var(--accent-2);
  border-left: 4px solid var(--accent);
  padding-left: 0.75rem;
  margin-top: 3rem;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}
.card {
  background: var(--card);
  padding: 1.5rem;
  border-radius: 10px;
  border: 1px solid #3a2820;
  transition: transform 0.15s, border-color 0.15s;
  display: block;
  text-decoration: none;
  color: inherit;
}
.card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
}
.card h3 { margin: 0 0 0.5rem; color: var(--accent-2); font-size: 1.15rem; }
.card p  { margin: 0 0 0.75rem; color: var(--text); font-size: 0.95rem; }
.card.stub { opacity: 0.55; cursor: not-allowed; }
.card.stub:hover { transform: none; border-color: #3a2820; }

.difficulty {
  display: inline-block;
  font-size: 0.75rem;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}
.easy   { background: #2d4a2d; color: #a8e6a8; }
.medium { background: #4a3d1f; color: #f4d68a; }
.hard   { background: #4a2522; color: #f4a8a3; }

footer {
  text-align: center;
  padding: 2rem 1.5rem;
  color: var(--muted);
  border-top: 1px solid #3a2820;
  font-size: 0.9rem;
}

code {
  background: #0f0a07;
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.85em;
  color: var(--accent-2);
}
pre {
  background: #0f0a07;
  padding: 1rem 1.25rem;
  border-radius: 8px;
  overflow-x: auto;
  border-left: 3px solid var(--accent);
  font-size: 0.9rem;
}
pre code { background: none; padding: 0; color: var(--text); }

article.tutorial { max-width: 760px; margin: 0 auto; padding: 2.5rem 1.5rem 4rem; }
article.tutorial h1 { color: var(--accent-2); margin-bottom: 0.25rem; }
article.tutorial .meta { color: var(--muted); margin-bottom: 2rem; font-size: 0.95rem; }
article.tutorial h2 { margin-top: 2.5rem; font-size: 1.4rem; }
article.tutorial ul, article.tutorial ol { padding-left: 1.5rem; }
article.tutorial li { margin: 0.35rem 0; }
.callout {
  background: #2a1f17;
  border-left: 3px solid var(--accent-2);
  padding: 0.85rem 1rem;
  border-radius: 0 6px 6px 0;
  margin: 1.25rem 0;
  font-size: 0.95rem;
}
.back { display: inline-block; margin-bottom: 1.5rem; color: var(--muted); text-decoration: none; }
.back:hover { color: var(--accent-2); }