body {
  font-family: Arial, sans-serif;
  background-color: #f5f5f5;
  color: #222;
  margin: 0;
  padding: 0;
}

header {
  background-color: #e2e8f0;
  padding: 20px;
  text-align: center;
}

h1 {
  text-align: center;
  color: #333;
  text-shadow: 1px 1px 2px #aaa;
  letter-spacing: 1px;
  margin-bottom: 10px;
}

h2 {
  color: #444;
  margin-top: 20px;
}

h3 {
  color: #555;
  margin-top: 15px;
}

p {
  line-height: 1.6;
  font-size: 1rem;
}

ul, ol, dl {
  margin: 10px 25px;
  padding: 5px;
}

ul {
  list-style-type: disc;
  list-style-position: inside;
}

ol {
  list-style-type: decimal;
  list-style-position: inside;
}

a {
  color: #1d4ed8;
}

nav {
  background-color: #1e293b;
  padding: 12px;
  text-align: center;
  margin-top: 10px;
}

nav a {
  color: white;
  text-decoration: none;
  margin: 0 10px;
  font-weight: bold;
}

nav a:hover {
  color: #facc15;
  text-decoration: underline;
  transition: 0.3s;
}

main {
  margin: 15px;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}

section {
  background-color: white;
  padding: 15px;
  border-radius: 8px;
  margin-bottom: 15px;
}

footer {
  text-align: center;
  margin-top: 20px;
  padding: 12px;
  background-color: #e5e7eb;
}

#intro {
  font-style: italic;
  color: #555;
}

.highlight {
  background-color: #fff1f2;
  padding: 4px 8px;
  font-weight: bold;
  display: inline-block;
}

img {
  max-width: 100%;
  height: auto;
}

/* Responsive */
@media (max-width: 768px) {
  body {
    font-size: 0.95rem;
  }

  nav a {
    display: block;
    margin: 8px 0;
  }

  main {
    margin: 10px;
  }
}