:root {
  --primary: #003366;
  --secondary: #0066cc;
  --accent: #ff9900;
  --light: #f8f9fa;
}

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  background: linear-gradient(135deg, var(--light) 0%, #e9ecef 100%);
}

.hero-section {
  position: relative;
  background: linear-gradient(rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.6)),
              url('https://images.unsplash.com/photo-1590579491624-f98f36d4c763');
  background-size: cover;
  background-position: center;
  color: white;
  padding: 4rem 0;
  margin-bottom: 2rem;
}

.study-section {
  background: linear-gradient(rgba(255, 255, 255, 0.9), rgba(255, 255, 255, 0.9)),
              url('https://images.unsplash.com/photo-1721702754494-fdd7189f946c');
  background-size: cover;
  background-position: center;
  padding: 2rem;
  border-radius: 1rem;
  margin: 2rem 0;
}

.calculator-card {
  background: white;
  border-radius: 1rem;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s ease;
  margin-bottom: 2rem;
  overflow: hidden;
}

.calculator-card:hover {
  transform: translateY(-5px);
}

.calculator-header {
  background: var(--primary);
  color: white;
  padding: 1.5rem;
  border-radius: 1rem 1rem 0 0;
}

.calculator-body {
  padding: 2rem;
}

.form-control {
  border-radius: 0.5rem;
  border: 2px solid #dee2e6;
  transition: all 0.3s ease;
}

.form-control:focus {
  border-color: var(--secondary);
  box-shadow: 0 0 0 0.2rem rgba(0, 102, 204, 0.25);
}

.btn-calculate {
  background: var(--secondary);
  color: white;
  border-radius: 0.5rem;
  padding: 0.75rem 1.5rem;
  transition: all 0.3s ease;
}

.btn-calculate:hover {
  background: var(--primary);
  transform: scale(1.05);
}

.alert {
  display: none;
  padding: 1rem;
  margin: 1rem 0;
  border-radius: 0.5rem;
  animation: fadeIn 0.3s ease-in-out;
}

.alert-success {
  background-color: #d4edda;
  border-color: #c3e6cb;
  color: #155724;
}

.alert-danger {
  background-color: #f8d7da;
  border-color: #f5c6cb;
  color: #721c24;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

.flash-messages {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1050;
    max-width: 350px;
}

.flash-messages .alert {
    margin-bottom: 10px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    display: block !important;
}

.footer {
  background: var(--primary);
  color: white;
  padding: 2rem 0;
  margin-top: 3rem;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.social-link {
    color: white;
    font-size: 1.5rem;
    transition: transform 0.3s ease, color 0.3s ease;
    text-decoration: none;
}

.social-link:hover {
    color: var(--accent);
    transform: scale(1.2);
}

.email-text {
    color: white;
    font-size: 0.9rem;
    opacity: 0.9;
}

.announcement-item {
  background-color: rgba(255, 255, 255, 0.8);
  border-radius: 0.5rem;
  padding: 1rem;
  margin: 1rem 0;
  border: 1px solid rgba(0, 51, 102, 0.1);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
  transition: transform 0.2s ease;
}

.announcement-item:hover {
  transform: translateX(5px);
  background-color: rgba(255, 255, 255, 0.9);
}

.announcement-item .fas {
  color: var(--primary);
}

.btn-danger {
  background-color: #dc3545;
  border-color: #dc3545;
  color: white;
}

.btn-danger:hover {
  background-color: #bb2d3b;
  border-color: #b02a37;
}

@media (max-width: 768px) {
  .calculator-card {
    margin: 1rem 0;
  }
  
  .hero-section {
    padding: 2rem 0;
  }
}