:root {
  --primary-color: #2c3e50;
  --secondary-color: #34495e;
  --accent-color: #3498db;
  --text-color: #333;
  --background-color: #f5f6fa;
  --white: #ffffff;
}

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

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--background-color);
  padding: 20px;
}

header {
  background-color: var(--primary-color);
  color: var(--white);
  padding: 20px 0;
  text-align: center;
}

nav ul {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 20px;
  padding: 10px;
}

nav a {
  color: var(--white);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
}

nav a:hover {
  color: var(--accent-color);
}

main {
  max-width: 800px;
  margin: 40px auto;
  padding: 20px;
  background-color: var(--white);
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

h1, h2 {
  color: var(--primary-color);
  margin-bottom: 20px;
}

.profile p {
  margin: 10px 0;
}

.timeline {
  margin: 20px 0;
}

.event {
  margin-bottom: 30px;
  padding-left: 20px;
  border-left: 2px solid var(--accent-color);
}

.event h3 {
  color: var(--secondary-color);
  margin-bottom: 10px;
}

ul {
  list-style: none;
  padding-left: 20px;
}

footer {
  text-align: center;
  padding: 20px;
  color: var(--white);
  background-color: var(--primary-color);
  margin-top: 40px;
}

@media (max-width: 600px) {
  nav ul {
    flex-direction: column;
    gap: 10px;
  }
  
  main {
    padding: 15px;
  }
}