:root {
  --bg: #f5f7fa;
  --card: #ffffff;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --accent: #007aff;
  --accent-dark: #005ecb;
  --border: #e5e5ea;
  --max: 760px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-size: 16px;
}

header {
  background: linear-gradient(135deg, #007aff 0%, #5856d6 55%, #1a1a2e 100%);
  color: #fff;
  padding: 2rem 1.25rem 1.75rem;
}

header .wrap { max-width: var(--max); margin: 0 auto; }
header h1 { margin: 0 0 0.35rem; font-size: 1.65rem; font-weight: 700; }
header p { margin: 0; opacity: 0.92; font-size: 0.95rem; }

nav {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0.85rem 1.25rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  font-size: 0.875rem;
}

nav a { color: var(--accent); text-decoration: none; }
nav a:hover { text-decoration: underline; }

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

article {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1.75rem 1.5rem;
  margin-top: 1rem;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

article h2 { font-size: 1.15rem; margin: 1.75rem 0 0.65rem; }
article h3 { font-size: 1rem; margin: 1.25rem 0 0.5rem; }
article ul, article ol { padding-left: 1.25rem; }
article a { color: var(--accent); }
article code { font-size: 0.88em; background: var(--bg); padding: 0.1em 0.35em; border-radius: 4px; }

.meta { color: var(--muted); font-size: 0.875rem; margin-bottom: 1.25rem; }
.note { color: var(--muted); font-size: 0.875rem; padding: 0.75rem 1rem; background: var(--bg); border-radius: 8px; border-left: 3px solid var(--accent); }

.lang-divider { border: 0; border-top: 2px dashed var(--border); margin: 2.5rem 0 2rem; }

footer {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 1.25rem 2.5rem;
  color: var(--muted);
  font-size: 0.8125rem;
  text-align: center;
}

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

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f0f12;
    --card: #1c1c1e;
    --text: #f5f5f7;
    --muted: #98989d;
    --border: #38383a;
  }
}