:root {
  color-scheme: light;
  --text: #1c1917;
  --muted: #57534e;
  --border: #d6d3d1;
  --background: #f5f5f4;
  --card: #ffffff;
  --accent: #1d4ed8;
  --accent-soft: #eff6ff;
  --note-bg: #fef3c7;
  --note-border: #f59e0b;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: system-ui, "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC",
    sans-serif;
  line-height: 1.7;
  color: var(--text);
  background: var(--background);
}

.page {
  max-width: 56rem;
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}

a {
  color: var(--accent);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.15em;
}

a:hover {
  text-decoration-thickness: 0.15em;
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 2px;
}

.hero {
  padding: 1.5rem 0 1rem;
}

h1 {
  margin: 0 0 0.25rem;
  font-size: 1.75rem;
  line-height: 1.25;
}

.subtitle {
  margin: 0;
  color: var(--muted);
}

.notice {
  margin: 1rem 0 0;
  padding: 0.75rem 1rem;
  border: 1px solid var(--note-border);
  border-left-width: 4px;
  background: var(--note-bg);
  border-radius: 0.375rem;
}

section {
  margin-top: 2.5rem;
}

h2 {
  margin: 0 0 0.75rem;
  font-size: 1.25rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.375rem;
}

p,
ul,
ol {
  margin: 0.5rem 0;
}

ul,
ol {
  padding-left: 1.5rem;
}

li {
  margin: 0.25rem 0;
}

code,
pre {
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  font-size: 0.9em;
}

code {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 0.25rem;
  padding: 0.1em 0.35em;
}

.diagram {
  margin: 0.75rem 0;
  padding: 1rem 1.25rem;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  overflow-x: auto;
  line-height: 1.45;
  font-size: 0.85rem;
}

.stack {
  display: grid;
  gap: 0.25rem;
}

figure {
  margin: 1.25rem 0;
}

figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  background: var(--card);
}

figcaption {
  margin-top: 0.375rem;
  font-size: 0.875rem;
  color: var(--muted);
}

footer {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.875rem;
}

@media (max-width: 40rem) {
  .page {
    padding: 1.25rem 0.875rem 2rem;
  }

  h1 {
    font-size: 1.4rem;
  }

  section {
    margin-top: 2rem;
  }
}