:root {
  --primary-color: #7c3aed;
  --primary-dark: #6d28d9;
  --secondary-color: #a78bfa;
  --text-dark: #1f2937;
  --text-light: #6b7280;
  --bg-light: #f9fafb;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--text-dark);
  line-height: 1.6;
  padding-top: 70px;
}

.navbar-brand {
  font-size: 1.5rem;
  color: var(--primary-color) !important;
}

.nav-link {
  color: var(--text-dark) !important;
  font-weight: 500;
  transition: color 0.3s ease;
}

.nav-link:hover,
.nav-link.active {
  color: var(--primary-color) !important;
}

.btn-primary {
  background-color: var(--primary-color);
  border-color: var(--primary-color);
  transition: all 0.3s ease;
}

.btn-primary:hover {
  background-color: var(--primary-dark);
  border-color: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(124, 58, 237, 0.3);
}

.btn-outline-primary {
  color: var(--primary-color);
  border-color: var(--primary-color);
  transition: all 0.3s ease;
}

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

.text-primary {
  color: var(--primary-color) !important;
}

.bg-primary {
  background-color: var(--primary-color) !important;
}

.hero-section {
  padding: 100px 0;
  background: linear-gradient(135deg, #f9fafb 0%, #e0e7ff 100%);
}

.page-header {
  padding: 120px 0 60px;
  background: linear-gradient(135deg, #7c3aed 0%, #a78bfa 100%);
  color: white;
  text-align: center;
}

.card {
  border: none;
  border-radius: 12px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.shadow-sm {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.shadow {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
}

.cert-box {
  background: white;
  border-radius: 12px;
  transition: all 0.3s ease;
}

.cert-box:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 20px rgba(124, 58, 237, 0.15);
}

.thank-you-section {
  padding: 150px 0 100px;
  min-height: 70vh;
}

.thank-you-icon {
  animation: checkmark 0.8s ease-in-out;
}

@keyframes checkmark {
  0% {
    transform: scale(0);
  }
  50% {
    transform: scale(1.2);
  }
  100% {
    transform: scale(1);
  }
}

footer {
  margin-top: auto;
}

footer a {
  text-decoration: none;
  transition: opacity 0.3s ease;
}

footer a:hover {
  opacity: 0.8;
}

.form-control:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 0.2rem rgba(124, 58, 237, 0.25);
}

.custom-control-input:checked ~ .custom-control-label::before {
  background-color: var(--primary-color);
  border-color: var(--primary-color);
}

#bmiResult .alert {
  border-radius: 12px;
  font-size: 1.1rem;
}

.bmi-category {
  font-weight: bold;
  font-size: 1.3rem;
}

@media (max-width: 768px) {
  .hero-section {
    padding: 60px 0;
  }

  .page-header {
    padding: 100px 0 40px;
  }

  .display-4 {
    font-size: 2rem;
  }

  body {
    padding-top: 56px;
  }
}

@media (max-width: 576px) {
  .btn-lg {
    font-size: 1rem;
    padding: 0.5rem 1rem;
  }

  .display-4 {
    font-size: 1.75rem;
  }
}