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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  line-height: 1.6;
  color: #333;
  background-color: #f8f9fa;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  background-color: #fff;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  margin-bottom: 2rem;
  border-radius: 8px;
  margin-top: 1rem;
  padding: 1.5rem;
}

header h1 {
  color: #e74c3c;
  margin-bottom: 1rem;
  text-align: center;
}

nav {
  display: flex;
  justify-content: center;
  gap: 2rem;
}

nav a {
  text-decoration: none;
  color: #666;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  transition: all 0.3s ease;
}

nav a:hover,
nav a.active {
  background-color: #e74c3c;
  color: white;
}

main {
  flex: 1;
  background-color: #fff;
  border-radius: 8px;
  padding: 2rem;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.language-switcher {
  display: flex;
  justify-content: center;
  margin-bottom: 2rem;
  gap: 0;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  width: fit-content;
  margin-left: auto;
  margin-right: auto;
}

.language-switcher button {
  padding: 0.75rem 1.5rem;
  border: none;
  background-color: #f8f9fa;
  color: #666;
  cursor: pointer;
  transition: all 0.3s ease;
  font-weight: 500;
}

.language-switcher button.active {
  background-color: #e74c3c;
  color: white;
}

.language-switcher button:hover:not(.active) {
  background-color: #e9ecef;
}

.content {
  animation: fadeIn 0.3s ease-in;
}

.content.hidden {
  display: none;
}

.last-updated {
  color: #666;
  font-size: 0.9rem;
  margin-bottom: 2rem;
  text-align: center;
  font-style: italic;
}

h1 {
  color: #e74c3c;
  margin-bottom: 1rem;
  text-align: center;
  font-size: 2.5rem;
}

h2 {
  color: #2c3e50;
  margin: 2rem 0 1rem 0;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid #ecf0f1;
}

h3 {
  color: #34495e;
  margin: 1.5rem 0 0.5rem 0;
}

section {
  margin-bottom: 2rem;
}

ul {
  margin-left: 1.5rem;
  margin-bottom: 1rem;
}

li {
  margin-bottom: 0.5rem;
}

a {
  color: #e74c3c;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

footer {
  text-align: center;
  padding: 2rem 0;
  margin-top: 2rem;
  color: #666;
  border-top: 1px solid #ecf0f1;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
  .container {
      padding: 0 15px;
  }
  
  header {
      margin-top: 0.5rem;
      padding: 1rem;
  }
  
  nav {
      flex-direction: column;
      gap: 0.5rem;
      align-items: center;
  }
  
  main {
      padding: 1.5rem;
  }
  
  h1 {
      font-size: 2rem;
  }
  
  .language-switcher {
      margin-bottom: 1.5rem;
  }
}