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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Hiragino Sans", "Noto Sans CJK JP", sans-serif;
  line-height: 1.8;
  color: #333;
  background-color: #f8f9fa;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 20px;
}

header {
  text-align: center;
  padding: 60px 20px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
}

header h1 {
  font-size: 2rem;
  margin-bottom: 10px;
}

header p {
  opacity: 0.9;
}

nav {
  background: white;
  padding: 15px;
  text-align: center;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

nav a {
  color: #667eea;
  text-decoration: none;
  margin: 0 15px;
  font-weight: 500;
}

nav a:hover {
  text-decoration: underline;
}

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

h1 {
  color: #333;
  margin-bottom: 30px;
  padding-bottom: 15px;
  border-bottom: 2px solid #667eea;
}

h2 {
  color: #444;
  margin-top: 30px;
  margin-bottom: 15px;
  font-size: 1.3rem;
}

p {
  margin-bottom: 15px;
}

ul {
  margin-left: 20px;
  margin-bottom: 15px;
}

li {
  margin-bottom: 8px;
}

footer {
  text-align: center;
  padding: 30px;
  color: #666;
  font-size: 0.9rem;
}

footer a {
  color: #667eea;
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}

.links {
  display: flex;
  justify-content: center;
  gap: 30px;
  margin-top: 30px;
}

.links a {
  color: #667eea;
  text-decoration: none;
  padding: 12px 24px;
  border: 2px solid #667eea;
  border-radius: 6px;
  transition: all 0.3s;
}

.links a:hover {
  background: #667eea;
  color: white;
}