* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  color: #333;
  background: #f5f5f5;
}

header {
  background: #2c3e50;
  color: white;
  padding: 1.5rem 1rem;
  text-align: center;
}

header .container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0;
  background: transparent;
  min-height: auto;
}

header h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

header p {
  font-size: 1.2rem;
  color: #ecf0f1;
}

nav {
  background: #34495e;
  padding: 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

nav ul {
  list-style: none;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
}

nav li {
  margin: 0;
}

nav a {
  display: block;
  color: white;
  text-decoration: none;
  padding: 1rem 1.5rem;
  transition: background 0.3s;
}

nav a:hover {
  background: #2c3e50;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem 1rem;
  background: white;
  min-height: 100vh;
}

section {
  margin-bottom: 3rem;
}

h2 {
  color: #2c3e50;
  font-size: 2rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 3px solid #3498db;
}

h3 {
  color: #34495e;
  font-size: 1.5rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
}

h4 {
  color: #555;
  font-size: 1.2rem;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

p {
  margin-bottom: 1rem;
}

ul {
  margin-left: 2rem;
  margin-bottom: 1rem;
}

li {
  margin-bottom: 0.5rem;
}

a {
  color: #3498db;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

strong {
  color: #2c3e50;
}

em {
  color: #7f8c8d;
}

@media (max-width: 768px) {
  header h1 {
    font-size: 2rem;
  }
  
  header p {
    font-size: 1rem;
  }
  
  nav a {
    padding: 0.75rem 1rem;
    font-size: 0.9rem;
  }
  
  .container {
    padding: 1rem;
  }
  
  h2 {
    font-size: 1.5rem;
  }
  
  h3 {
    font-size: 1.25rem;
  }
}