:root {
  --bg-color: #f4f4f5;
  --text-color: #1a1a1a;
  --primary: #004085;
  --danger: #d73a49;
  --success: #28a745;
  --card-bg: #ffffff;
  --border: #e1e4e8;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--bg-color);
  margin: 0;
  padding: 0;
}

header {
  background-color: var(--card-bg);
  padding: 2rem;
  border-bottom: 1px solid var(--border);
  text-align: center;
}

main {
  max-width: 1200px;
  margin: 2rem auto;
  padding: 0 1rem;
}

.module-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.module-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.5rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}

.module-card h2 {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.module-card p {
  color: #586069;
  margin-bottom: 1.5rem;
  font-size: 0.9rem;
}

.links {
  display: flex;
  gap: 0.5rem;
}

.btn {
  display: inline-block;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  text-align: center;
  flex: 1;
}

.btn-issue {
  background-color: #ffeef0;
  color: var(--danger);
  border: 1px solid rgba(215, 58, 73, 0.2);
}

.btn-fixed {
  background-color: #eafeed;
  color: var(--success);
  border: 1px solid rgba(40, 167, 69, 0.2);
}

.btn:hover {
  opacity: 0.8;
}

/* Common styles for test pages */
.test-container {
  max-width: 800px;
  margin: 2rem auto;
  background: white;
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.test-header {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 2px solid var(--border);
}

.back-link {
  display: inline-block;
  margin-bottom: 1rem;
  color: var(--primary);
  text-decoration: none;
}

.back-link:hover {
  text-decoration: underline;
}