/* Reset and base styling */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  font-family: 'Segoe UI', Tahoma, sans-serif;
  background-color: #f4f4f5;
  color: #1a1a1a;
  line-height: 1.7;
  font-size: 16px;
  padding-bottom: 50px;
}
header {
  background-color: #222;
  color: #fff;
  text-align: center;
  padding: 60px 20px;
}
header h1 {
  font-size: 2.8em;
  font-weight: 600;
}
header p {
  margin-top: 10px;
  font-size: 1.2em;
  color: #ccc;
}
nav {
  text-align: center;
  margin-top: -20px;
  background-color: #f9f9f9;
  padding: 15px 0;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.03);
}
nav ul {
  list-style: none;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
}
nav ul li {
  margin: 0 20px;
}
nav ul li a {
  color: #333;
  text-decoration: none;
  font-weight: 500;
  font-size: 1.05em;
}
nav ul li a:hover {
  color: #4CAF50;
}
section {
  max-width: 850px;
  margin: 40px auto;
  padding: 30px;
  background-color: #fff;
  border-radius: 8px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}
section h2 {
  font-size: 1.8em;
  margin-bottom: 20px;
  color: #222;
  border-bottom: 2px solid #e5e5e5;
  padding-bottom: 8px;
}
section ul {
  list-style-type: disc;
  padding-left: 20px;
}
section ul li {
  margin-bottom: 10px;
  font-size: 1.05em;
}
section ul li ul {
  margin-top: 10px;
  list-style-type: circle;
}
footer {
  background-color: #222;
  color: white;
  text-align: center;
  padding: 20px;
  font-size: 0.95em;
  position: relative;
}
footer a {
  color: #4CAF50;
  text-decoration: none;
}
footer a:hover {
  text-decoration: underline;
}
details {
  margin-bottom: 15px;
}
details summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 1.1em;
  color: #4CAF50;
  margin-bottom: 10px;
}
details[open] summary {
  color: #2e7d32;
}