/* Reset and Base Styles */
* {
  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: #ffffff;
  background: #121212;
  min-height: 100vh;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 20px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 40px;
  padding: 20px 0;
  border-bottom: 2px solid #333333;
}

.logo h1 {
  font-size: 2.5rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 5px;
}

.logo .japanese {
  color: #6b7aee;
  font-size: 2rem;
}

.logo .subtitle {
  color: #bbbbbb;
  font-size: 1rem;
  font-weight: 400;
}

/* Language Selector */
.language-selector {
  display: flex;
  gap: 10px;
  background: #1e1e1e;
  padding: 5px;
  border-radius: 12px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

.lang-btn {
  background: transparent;
  border: none;
  color: #bbbbbb;
  padding: 8px 16px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 500;
  transition: all 0.3s ease;
}

.lang-btn:hover {
  background: #333333;
  color: #ffffff;
}

.lang-btn.active {
  background: #6b7aee;
  color: #ffffff;
  box-shadow: 0 2px 4px rgba(107, 122, 238, 0.3);
}

/* Main Content */
.main {
  flex: 1;
  margin-bottom: 40px;
}

.content {
  display: none;
  animation: fadeIn 0.5s ease-in-out;
}

.content.active {
  display: block;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Typography */
h2 {
  font-size: 2.2rem;
  color: #ffffff;
  margin-bottom: 10px;
  font-weight: 600;
}

h3 {
  font-size: 1.5rem;
  color: #ffffff;
  margin-bottom: 15px;
  font-weight: 600;
}

h4 {
  font-size: 1.2rem;
  color: #f3f4f6;
  margin-bottom: 10px;
  font-weight: 500;
}

.last-updated {
  color: #bbbbbb;
  font-size: 0.9rem;
  margin-bottom: 30px;
  font-style: italic;
}

/* Sections */
.section {
  margin-bottom: 40px;
  padding: 25px;
  background: #1e1e1e;
  border-radius: 16px;
  border: 1px solid #333333;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.section:hover {
  border-color: #6b7aee;
  box-shadow: 0 8px 12px rgba(0, 0, 0, 0.2);
  transition: all 0.3s ease;
}

p {
  margin-bottom: 15px;
  color: #ffffff;
  line-height: 1.7;
}

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

li {
  margin-bottom: 8px;
  color: #ffffff;
  line-height: 1.6;
}

li strong {
  color: #ffffff;
  font-weight: 600;
}

/* Footer */
.footer {
  text-align: center;
  padding: 20px 0;
  border-top: 2px solid #333333;
  color: #bbbbbb;
  font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 15px;
  }

  .header {
    flex-direction: column;
    gap: 20px;
    text-align: center;
  }

  .logo h1 {
    font-size: 2rem;
  }

  .logo .japanese {
    font-size: 1.5rem;
  }

  .language-selector {
    width: 100%;
    justify-content: center;
  }

  .lang-btn {
    flex: 1;
    text-align: center;
  }

  h2 {
    font-size: 1.8rem;
  }

  h3 {
    font-size: 1.3rem;
  }

  .section {
    padding: 20px;
    margin-bottom: 30px;
  }
}

@media (max-width: 480px) {
  .logo h1 {
    font-size: 1.8rem;
  }

  .logo .japanese {
    font-size: 1.3rem;
  }

  h2 {
    font-size: 1.6rem;
  }

  h3 {
    font-size: 1.2rem;
  }

  .section {
    padding: 15px;
  }

  .lang-btn {
    font-size: 0.8rem;
    padding: 6px 12px;
  }
}

/* Scroll Behavior */
html {
  scroll-behavior: smooth;
}

/* Selection Color */
::selection {
  background: rgba(107, 122, 238, 0.3);
  color: #ffffff;
}

/* Focus States */
.lang-btn:focus {
  outline: 2px solid #6b7aee;
  outline-offset: 2px;
}

/* Print Styles */
@media print {
  body {
    background: white;
    color: black;
  }

  .header,
  .footer {
    border-color: #ccc;
  }

  .section {
    background: white;
    border: 1px solid #ccc;
    box-shadow: none;
  }

  .language-selector {
    display: none;
  }

  .content:not(.active) {
    display: none !important;
  }
}