:root {
  --bg: #ffffff;
  --fg: #1b1b1b;
  --muted: #5d5d5d;
  --rule: #e3e3e3;
  --accent: #0f6cbd;
  --code-bg: #f6f6f6;
  --good: #107c41;
  --good-bg: #f1f8f3;
  --bad: #c4314b;
  --bad-bg: #fdf3f4;
  --maxw: 44rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #171717;
    --fg: #e8e8e8;
    --muted: #a3a3a3;
    --rule: #333333;
    --accent: #6cb8f6;
    --code-bg: #1f1f1f;
    --good: #5bc47f;
    --good-bg: #16231a;
    --bad: #f1707f;
    --bad-bg: #251619;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
}

.site-header {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 1.75rem 1.25rem 0.75rem;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.5rem 1.25rem;
  border-bottom: 1px solid var(--rule);
}

.wordmark {
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
  text-decoration: none;
  color: var(--fg);
}

.site-header nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 1rem;
  font-size: 0.85rem;
}

.site-header nav a {
  color: var(--muted);
  text-decoration: none;
}

.site-header nav a:hover { color: var(--accent); text-decoration: underline; }

main {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 1.5rem 1.25rem 3rem;
}

h1 {
  font-size: 2rem;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: 1.5rem 0 1rem;
}

h2 {
  font-size: 1.3rem;
  letter-spacing: -0.01em;
  margin: 2.75rem 0 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--rule);
}

h3 {
  font-size: 1.05rem;
  margin: 1.75rem 0 0.5rem;
}

p { margin: 0 0 1rem; }

a { color: var(--accent); }

ul, ol { margin: 0 0 1rem; padding-left: 1.4rem; }
li { margin-bottom: 0.4rem; }

.rule {
  border-left: 3px solid var(--accent);
  background: var(--code-bg);
  padding: 0.75rem 1rem;
  margin: 1.25rem 0;
  border-radius: 0 4px 4px 0;
}

pre {
  background: var(--code-bg);
  border: 1px solid var(--rule);
  border-radius: 6px;
  padding: 0.9rem 1rem;
  overflow-x: auto;
  margin: 0 0 1.25rem;
}

pre code {
  font-family: Consolas, "Cascadia Mono", Menlo, monospace;
  font-size: 0.82rem;
  line-height: 1.55;
  white-space: pre;
  color: inherit;
}

.chat { position: relative; padding-top: 2.1rem; }

.chat::before {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  padding: 0.3rem 1rem;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border-radius: 5px 5px 0 0;
}

.chat.bad { background: var(--bad-bg); border-color: var(--bad); }
.chat.bad::before { content: "\2717  Don't"; color: var(--bad); border-bottom: 1px solid var(--bad); }

.chat.good { background: var(--good-bg); border-color: var(--good); }
.chat.good::before { content: "\2713  Do this instead"; color: var(--good); border-bottom: 1px solid var(--good); }

.note { color: var(--muted); font-style: italic; }

.checklist li { margin-bottom: 0.55rem; }

footer {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 1.25rem 1.25rem 3rem;
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-size: 0.85rem;
}

footer p { margin: 0 0 0.35rem; }

@media (max-width: 480px) {
  body { font-size: 16px; }
  h1 { font-size: 1.6rem; }
  pre code { font-size: 0.74rem; }
}