* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 16px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: linear-gradient(135deg, #4FACFE 0%, #00F2FE 100%);
  min-height: 100vh;
  padding-top: max(16px, env(safe-area-inset-top));
  padding-bottom: max(16px, env(safe-area-inset-bottom));
}

.container {
  width: 100%;
  max-width: 700px;
  margin: 0 auto;
}

/* Header */
.header {
  text-align: center;
  margin-bottom: 32px;
  color: white;
}

.header h1 {
  margin: 0;
  font-size: 48px;
  font-weight: 700;
}

.header p {
  margin: 8px 0 0 0;
  font-size: 16px;
  opacity: 0.9;
}

/* Section Dividers */
.section-divider {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 16px;
}

.section-divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: rgba(255, 255, 255, 0.35);
}

.section-label {
  color: white;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

/* Version Cards */
.version-card {
  background: rgba(255, 255, 255, 0.97);
  border-radius: 16px;
  padding: 20px 20px 16px;
  margin-bottom: 20px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
  border-top: 5px solid #ccc;
}

.version-card--current {
  border-top-color: #16a34a;
}

.version-card--v2 {
  border-top-color: #2563eb;
}

.version-card--v1 {
  border-top-color: #9ca3af;
}

.version-card-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
}

.version-pill {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 3px 10px;
  border-radius: 20px;
  background: #f1f5f9;
  color: #475569;
}

.version-card--current .version-pill {
  background: #dcfce7;
  color: #15803d;
}

.version-card--v2 .version-pill {
  background: #dbeafe;
  color: #1d4ed8;
}

.version-date {
  font-size: 13px;
  color: #94a3b8;
  font-weight: 500;
}

.version-title {
  font-size: 20px;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 4px;
}

.version-subtitle {
  font-size: 14px;
  color: #64748b;
  margin-bottom: 16px;
  line-height: 1.5;
}

/* Feature Groups (v3 only) */
.feature-group {
  margin-bottom: 16px;
}

.feature-group:last-child {
  margin-bottom: 0;
}

.feature-group-label {
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #475569;
  margin-bottom: 6px;
}

/* Feature Lists */
.feature-list {
  margin: 0;
  padding: 0 0 0 18px;
  list-style: none;
}

.feature-list li {
  position: relative;
  padding-left: 14px;
  margin-bottom: 6px;
  font-size: 14px;
  color: #334155;
  line-height: 1.5;
}

.feature-list li:last-child {
  margin-bottom: 0;
}

.feature-list li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: #94a3b8;
  font-weight: 700;
}

.version-card--current .feature-group .feature-list li::before {
  color: #16a34a;
}

.version-card--v2 .feature-list li::before {
  color: #2563eb;
}

/* Back Button */
.back-button {
  display: block;
  width: 100%;
  padding: 16px 12px;
  font-size: 15px;
  font-weight: 700;
  border-radius: 10px;
  background: white;
  color: #4FACFE;
  text-decoration: none;
  text-align: center;
  margin-bottom: 32px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
  transition: box-shadow 0.2s, transform 0.2s;
  box-sizing: border-box;
}

.back-button:active {
  transform: scale(0.98);
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
}

@media (max-width: 480px) {
  .header h1 {
    font-size: 36px;
  }

  .section-label {
    font-size: 17px;
  }

  .version-title {
    font-size: 18px;
  }
}