body {
  font-family: 'Georgia', 'Times New Roman', serif;
  max-width: 900px;
  margin: 0 auto;
  padding: 40px 20px;
  line-height: 1.8;
  color: #333;
  background: #fafafa;
}
h1 {
  color: #2c3e50;
  border-bottom: 3px solid #3498db;
  padding-bottom: 10px;
  margin-bottom: 20px;
}
h2 {
  color: #34495e;
  margin-top: 30px;
  margin-bottom: 15px;
}
h3 {
  color: #555;
  margin-top: 25px;
  margin-bottom: 12px;
}
a {
  color: #3498db;
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}
blockquote {
  border-left: 4px solid #3498db;
  padding-left: 20px;
  margin-left: 0;
  color: #555;
  font-style: italic;
}
code {
  background: #f4f4f4;
  padding: 2px 6px;
  border-radius: 3px;
  font-family: 'Courier New', monospace;
}
pre {
  background: #f4f4f4;
  padding: 15px;
  border-radius: 5px;
  overflow-x: auto;
}
.navigation {
  background: #f8f9fa;
  border-top: 2px solid #3498db;
  border-bottom: 2px solid #3498db;
  padding: 20px;
  margin: 30px 0;
  text-align: center;
  border-radius: 5px;
}
.nav-links {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}
.nav-links a {
  display: inline-block;
  padding: 10px 20px;
  background: #3498db;
  color: white;
  text-decoration: none;
  border-radius: 5px;
  font-weight: bold;
  transition: background 0.3s;
}
.nav-links a:hover {
  background: #2980b9;
}
.nav-links .nav-home {
  background: #27ae60;
}
.nav-links .nav-home:hover {
  background: #229954;
}
.nav-links .nav-prev {
  background: #e67e22;
}
.nav-links .nav-prev:hover {
  background: #d35400;
}
.nav-links .nav-next {
  background: #9b59b6;
}
.nav-links .nav-next:hover {
  background: #8e44ad;
}
.nav-links span {
  flex: 1;
}
@media (max-width: 768px) {
  body {
    padding: 20px 10px;
  }
  .nav-links {
    flex-direction: column;
  }
  .nav-links a {
    width: 100%;
  }
}