.ui-style-5 {
  --primary-color: #3498db;
  --secondary-color: #2c3e50;
  --accent-color: #e74c3c;
  --bg-color: #f5f7fa;
  --text-color: #2c3e50;
  --border-radius: 8px;
}

body {
  font-size: 16px;
  overflow-x: hidden;
}

.container {
  animation: fadeIn 0.6s ease-in;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

h1, h2, h3 {
  font-weight: 600;
  letter-spacing: -0.02em;
}

button, .btn {
  background: var(--primary-color);
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: all 0.3s;
  font-size: 1rem;
}

button:hover, .btn:hover {
  background: #2980b9;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(52, 152, 219, 0.3);
}

.card {
  background: white;
  border-radius: var(--border-radius);
  padding: 1.5rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
  transition: all 0.3s;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.1);
}

@media (max-width: 768px) {
  body {
    font-size: 14px;
  }

  .container {
    padding: 1rem 0.5rem;
  }

  h1 {
    font-size: 1.5rem;
  }

  h2 {
    font-size: 1.2rem;
  }
}

@media (max-width: 480px) {
  nav a {
    font-size: 0.75rem;
    padding: 0.4rem 0.2rem;
  }

  .card {
    padding: 1rem;
  }
}

.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--primary-color);
  color: white;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: #2980b9;
  transform: translateY(-4px);
}