:root {
  --primary: #3b82f6;
  --primary-dark: #2563eb;
  --secondary: #10b981;
  --accent: #f59e0b;
  --background: #f8fafc;
  --surface: #ffffff;
  --text: #1e293b;
  --text-light: #64748b;
  --border: #e2e8f0;
  --shadow: rgba(0, 0, 0, 0.1);
  --error: #ef4444;
  --success: #10b981;
}

* {
  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: var(--text);
  background: var(--background);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}

header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: white;
  padding: 30px 20px;
  box-shadow: 0 2px 10px var(--shadow);
}

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

header .meta {
  font-size: 0.95rem;
  opacity: 0.9;
}

.role-switcher {
  background: white;
  padding: 15px 20px;
  margin: 20px 0;
  border-radius: 8px;
  box-shadow: 0 2px 8px var(--shadow);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 15px;
}

.role-switcher .current-role {
  font-weight: 600;
  color: var(--primary);
}

.role-switcher button {
  background: var(--primary);
  color: white;
  border: none;
  padding: 10px 20px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.95rem;
  transition: background 0.3s;
}

.role-switcher button:hover {
  background: var(--primary-dark);
}

.card {
  background: var(--surface);
  border-radius: 12px;
  padding: 25px;
  margin: 20px 0;
  box-shadow: 0 2px 8px var(--shadow);
  border: 1px solid var(--border);
}

.card h2 {
  color: var(--primary);
  margin-bottom: 15px;
  font-size: 1.5rem;
}

.card h3 {
  color: var(--text);
  margin: 20px 0 10px 0;
  font-size: 1.2rem;
}

.nav-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
  margin: 30px 0;
}

.nav-card {
  background: var(--surface);
  border-radius: 12px;
  padding: 25px;
  box-shadow: 0 2px 8px var(--shadow);
  border: 2px solid var(--border);
  cursor: pointer;
  transition: all 0.3s;
  text-decoration: none;
  color: inherit;
  display: block;
}

.nav-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 16px var(--shadow);
  border-color: var(--primary);
}

.nav-card h3 {
  color: var(--primary);
  margin: 0 0 10px 0;
}

.nav-card p {
  color: var(--text-light);
  font-size: 0.95rem;
}

.badge {
  display: inline-block;
  background: var(--accent);
  color: white;
  padding: 4px 12px;
  border-radius: 12px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-left: 10px;
}

.list-styled {
  list-style: none;
  padding-left: 0;
}

.list-styled li {
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  padding-left: 25px;
  position: relative;
}

.list-styled li:before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--success);
  font-weight: bold;
}

.btn {
  background: var(--primary);
  color: white;
  border: none;
  padding: 12px 24px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1rem;
  transition: all 0.3s;
  font-weight: 600;
}

.btn:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
}

.btn-secondary {
  background: var(--secondary);
}

.btn-secondary:hover {
  background: #059669;
}

.quiz-option {
  background: var(--surface);
  border: 2px solid var(--border);
  padding: 15px;
  margin: 10px 0;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s;
}

.quiz-option:hover {
  border-color: var(--primary);
  background: #eff6ff;
}

.quiz-option.correct {
  border-color: var(--success);
  background: #ecfdf5;
}

.quiz-option.incorrect {
  border-color: var(--error);
  background: #fef2f2;
}

.feedback {
  padding: 15px;
  border-radius: 8px;
  margin: 15px 0;
  font-weight: 500;
}

.feedback.success {
  background: #ecfdf5;
  color: #059669;
  border-left: 4px solid var(--success);
}

.feedback.error {
  background: #fef2f2;
  color: #dc2626;
  border-left: 4px solid var(--error);
}

.collapsible {
  cursor: pointer;
  padding: 15px;
  background: #eff6ff;
  border: none;
  text-align: left;
  width: 100%;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  margin: 10px 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.collapsible:hover {
  background: #dbeafe;
}

.collapsible-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  padding: 0 15px;
}

.collapsible-content.active {
  max-height: 2000px;
  padding: 15px;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
}

table th,
table td {
  padding: 12px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

table th {
  background: #eff6ff;
  color: var(--primary);
  font-weight: 600;
}

@media (max-width: 768px) {
  .nav-grid {
    grid-template-columns: 1fr;
  }
  header h1 {
    font-size: 1.5rem;
  }