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

/* ── Design tokens (light) ──────────────────────────────── */
:root {
  --bg: #fff;
  --bg-2: #f8f8f8;
  --bg-3: #f0f0f0;
  --text: #111;
  --text-2: #444;
  --text-3: #888;
  --border: #e5e5e5;
  --accent: #2563eb;
  --font: system-ui, -apple-system, sans-serif;
  --mono: 'Menlo', 'Monaco', monospace;
}

/* ── Design tokens (dark) ───────────────────────────────── */
[data-theme="dark"] {
  --bg: #111;
  --bg-2: #1a1a1a;
  --bg-3: #222;
  --text: #f0f0f0;
  --text-2: #aaa;
  --text-3: #666;
  --border: #2a2a2a;
  --accent: #60a5fa;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  transition: background 0.2s, color 0.2s;
}

nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 40px;
  border-bottom: 1px solid var(--border);
}
nav a { font-size: 0.8125rem; color: var(--text-3); text-decoration: none; }
nav a:hover { color: var(--text); }
.mode-toggle {
  background: var(--bg-2);
  border: 1px solid var(--border);
  padding: 6px 10px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1rem;
  transition: background 0.15s;
}
.mode-toggle:hover { background: var(--bg-3); }

main { max-width: 820px; margin: 0 auto; padding: 0 40px 80px; }
.page-header { padding: 60px 0 48px; border-bottom: 1px solid var(--border); margin-bottom: 40px; }
.label { font-size: 0.72rem; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-3); margin-bottom: 16px; }
h1 { font-size: 1.875rem; letter-spacing: -0.03em; margin-bottom: 12px; }
.sub { font-size: 0.9375rem; color: var(--text-2); max-width: 560px; line-height: 1.65; }

/* Comparison grid */
.comparison {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  margin-bottom: 48px;
}
.col-header { margin-bottom: 16px; }
.col-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 3px 8px;
  border-radius: 3px;
  margin-bottom: 6px;
}
.col-badge.hardcoded { background: #fef2f2; color: #dc2626; }
.col-badge.context { background: #f0fdf4; color: #16a34a; }
.col-note { display: block; font-size: 0.78rem; color: var(--text-3); margin-top: 6px; }

/* Card with hardcoded values — breaks in dark mode */
.card-hardcoded {
  background: #ffffff;
  border: 1px solid #e5e5e5;
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 16px;
}
.card-hardcoded .card-tag { font-size: 0.72rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: #888888; margin-bottom: 10px; }
.card-hardcoded .card-title { font-size: 1rem; font-weight: 600; color: #111111; margin-bottom: 8px; }
.card-hardcoded .card-desc { font-size: 0.8125rem; color: #555555; line-height: 1.55; margin-bottom: 16px; }
.card-hardcoded .card-footer { display: flex; align-items: center; justify-content: space-between; }
.card-hardcoded .card-lessons { font-size: 0.75rem; color: #888888; }
.card-hardcoded .card-cta { font-size: 0.8125rem; color: #2563eb; text-decoration: none; font-weight: 500; }
.card-hardcoded .card-cta:hover { color: #1d4ed8; }

/* Card with CSS tokens — adapts to dark mode */
.card-tokens {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 16px;
  transition: background 0.2s, border-color 0.2s;
}
.card-tokens .card-tag { font-size: 0.72rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--text-3); margin-bottom: 10px; }
.card-tokens .card-title { font-size: 1rem; font-weight: 600; color: var(--text); margin-bottom: 8px; }
.card-tokens .card-desc { font-size: 0.8125rem; color: var(--text-2); line-height: 1.55; margin-bottom: 16px; }
.card-tokens .card-footer { display: flex; align-items: center; justify-content: space-between; }
.card-tokens .card-lessons { font-size: 0.75rem; color: var(--text-3); }
.card-tokens .card-cta { font-size: 0.8125rem; color: var(--accent); text-decoration: none; font-weight: 500; }
.card-tokens .card-cta:hover { opacity: 0.8; }

/* Code notes */
.code-note {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: auto;
  transition: background 0.2s, border-color 0.2s;
}
.code-note pre { padding: 14px 16px; }
.code-note code { font-family: var(--mono); font-size: 0.75rem; color: var(--text-2); line-height: 1.7; }

/* Prompt section */
.prompt-section { border-top: 1px solid var(--border); padding-top: 40px; }
h2 { font-size: 1rem; font-weight: 600; margin-bottom: 16px; }
.prompt-block {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: auto;
  transition: background 0.2s, border-color 0.2s;
}
.prompt-block pre { padding: 20px; }
.prompt-block code { font-family: var(--mono); font-size: 0.8rem; color: var(--text); line-height: 1.7; }

@media (max-width: 640px) {
  nav { padding: 16px 20px; }
  main { padding: 0 20px 60px; }
  .comparison { grid-template-columns: 1fr; }
}