body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: linear-gradient(135deg, #e9f0ff 0%, #f7f7f7 100%);
  color: #222;
  min-height: 100vh;
}
header {
  background: linear-gradient(90deg, #3b7ddd 60%, #5fa8ff 100%);
  color: #fff;
  padding: 1.2rem 1rem 1rem 1rem;
  text-align: center;
  border-bottom-left-radius: 18px;
  border-bottom-right-radius: 18px;
  box-shadow: 0 2px 8px rgba(59,125,221,0.08);
}
.container {
  max-width: 680px;
  margin: 2.2rem auto 2.5rem auto;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 24px rgba(59,125,221,0.08), 0 1.5px 4px rgba(0,0,0,0.03);
  padding: 2rem 1.3rem 1.5rem 1.3rem;
  transition: box-shadow 0.2s;
}
h1 { font-size: 2em; margin-bottom: 0.2em; letter-spacing: 1px; }
h2 {
  font-size: 1.18em;
  margin-top: 1.7em;
  margin-bottom: 0.7em;
  color: #3b7ddd;
  border-left: 4px solid #3b7ddd;
  padding-left: 0.5em;
  background: linear-gradient(90deg, #e9f0ff 60%, #fff 100%);
  border-radius: 3px;
}
ul { padding-left: 1.2em; }
li { margin-bottom: 1.1em; line-height: 1.7; }
pre {
  background: #f4f8ff;
  border-radius: 4px;
  padding: 0.7em 0.9em;
  overflow-x: auto;
  font-size: 1em;
  margin: 0.4em 0 0 0;
  border: 1px solid #e3eaf5;
  font-family: "JetBrains Mono", "Fira Mono", "Consolas", monospace;
  transition: background 0.2s;
}
code {
  background: #e9f0ff;
  border-radius: 3px;
  padding: 0.15em 0.4em;
  font-size: 0.97em;
  font-family: inherit;
}
.code-block {
  position: relative;
  margin-bottom: 0.5em;
}
.copy-btn {
  position: absolute;
  top: 8px;
  right: 10px;
  background: linear-gradient(90deg, #3b7ddd 60%, #5fa8ff 100%);
  color: #fff;
  border: none;
  border-radius: 3px;
  padding: 0.15em 0.8em;
  font-size: 0.93em;
  cursor: pointer;
  opacity: 0.85;
  box-shadow: 0 1px 4px rgba(59,125,221,0.10);
  transition: opacity 0.2s, background 0.2s;
}
.copy-btn:hover { opacity: 1; background: #2357a5; }
nav {
  margin-bottom: 1.5em;
  border-bottom: 1px solid #e3eaf5;
  padding-bottom: 0.5em;
}
nav ul {
  list-style: none;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 1.1em;
  justify-content: center;
}
nav li { margin: 0; }
nav a {
  color: #3b7ddd;
  text-decoration: none;
  font-weight: bold;
  padding: 0.2em 0.7em;
  border-radius: 3px;
  transition: background 0.2s, color 0.2s;
}
nav a:hover, nav a.active {
  background: #e9f0ff;
  color: #2357a5;
}
@media (max-width: 600px) {
  .container { padding: 1rem 0.2rem; }
  nav ul { flex-direction: column; gap: 0.3em; }
  h1 { font-size: 1.25em; }
  h2 { font-size: 1em; }
  pre { font-size: 0.95em; }
}