body {
  font-family: system-ui, -apple-system, sans-serif;
  line-height: 1.75;
  color: #2d2d2d;
  max-width: 860px;
  margin: 0 auto;
  padding: 20px 14px;
  background: #ffffff;
}

h1 {
  text-align: center;
  color: #111;
  margin: 1.2em 0 0.8em;
  font-size: 1.9em;
  border-bottom: 2px solid #eee;
  padding-bottom: 0.4em;
}

h2 {
  color: #1a1a1a;
  margin: 2.2em 0 1em;
  font-size: 1.55em;
  border-left: 5px solid #4a90e2;
  padding-left: 12px;
}

h3 {
  color: #222;
  margin: 1.8em 0 0.9em;
  font-size: 1.28em;
}

ul {
  padding-left: 1.6em;
  margin: 1em 0;
}

li {
  margin: 0.55em 0;
}

strong {
  color: #000;
}

.summary {
  background: #f0f7ff;
  border-left: 5px solid #3a8ee6;
  padding: 1.2em 1.4em;
  margin: 2em 0;
  border-radius: 6px;
  font-size: 1.05em;
}

.highlight {
  background: #fdfaf2;
  padding: 0.9em 1.2em;
  margin: 1.3em 0;
  border-radius: 6px;
  border: 1px solid #f0e8d0;
}

img {
  display: block;
  margin: 2.2em auto;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 4px 14px rgba(0,0,0,0.08);
}

/* 可选：版权信息样式 */
.copy-info {
  margin-top: 3em;
  text-align: center;
  font-size: 0.9em;
  color: #666;
}