/* Theme variables and custom properties */
:root {
  --primary-color: #3498db;
  --text-dark: rgb(33, 33, 33);
  --success-bg: hsl(142, 76%, 36%);
  --spacing-unit: 1rem;
}

/* Base element styling */
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  color: var(--text-dark);
  line-height: 1.6;
  margin: 0;
  padding: var(--spacing-unit);
}

.card {
  background: #ffffff;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  padding: calc(var(--spacing-unit) * 1.5);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

#main-heading {
  color: var(--primary-color);
  font-size: 2.5rem;
  font-weight: 600;
}

.btn-success {
  background-color: var(--success-bg);
  color: #fff;
  padding: 10px 20px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

/* Responsive design */
@media (max-width: 768px) {
  .card {
    padding: var(--spacing-unit);
  }

  #main-heading {
    font-size: 1.75rem;
  }
}
