body.ui-style-0 {
  --primary-color: #e74c3c;
  --secondary-color: #3498db;
  --bg-color: #f5f5f5;
  --text-color: #333;
  --card-bg: #fff;
}

body.ui-style-1 {
  --primary-color: #2ecc71;
  --secondary-color: #16a085;
  --bg-color: #ecf0f1;
  --text-color: #2c3e50;
  --card-bg: #fff;
}

body.ui-style-2 {
  --primary-color: #f39c12;
  --secondary-color: #d35400;
  --bg-color: #fef5e7;
  --text-color: #333;
  --card-bg: #fff;
}

body.ui-style-3 {
  --primary-color: #9b59b6;
  --secondary-color: #8e44ad;
  --bg-color: #f4ecf7;
  --text-color: #333;
  --card-bg: #fff;
}

body.ui-style-4 {
  --primary-color: #e67e22;
  --secondary-color: #d35400;
  --bg-color: #fef5e7;
  --text-color: #34495e;
  --card-bg: #fff;
}

body.ui-style-5 {
  --primary-color: #1abc9c;
  --secondary-color: #16a085;
  --bg-color: #e8f8f5;
  --text-color: #2c3e50;
  --card-bg: #fff;
}

body.ui-style-6 {
  --primary-color: #e74c3c;
  --secondary-color: #c0392b;
  --bg-color: #fadbd8;
  --text-color: #333;
  --card-bg: #fff;
}

body.ui-style-7 {
  --primary-color: #3498db;
  --secondary-color: #2980b9;
  --bg-color: #d6eaf8;
  --text-color: #2c3e50;
  --card-bg: #fff;
}

body.ui-style-8 {
  --primary-color: #34495e;
  --secondary-color: #2c3e50;
  --bg-color: #ecf0f1;
  --text-color: #333;
  --card-bg: #fff;
}

body.ui-style-9 {
  --primary-color: #c0392b;
  --secondary-color: #a93226;
  --bg-color: #f9ebea;
  --text-color: #333;
  --card-bg: #fff;
}

body.ui-style-10 {
  --primary-color: #27ae60;
  --secondary-color: #229954;
  --bg-color: #d5f4e6;
  --text-color: #2c3e50;
  --card-bg: #fff;
}

body.ui-style-11 {
  --primary-color: #f39c12;
  --secondary-color: #e67e22;
  --bg-color: #fef9e7;
  --text-color: #333;
  --card-bg: #fff;
}

body.ui-style-12 {
  --primary-color: #8e44ad;
  --secondary-color: #71368a;
  --bg-color: #ebdef0;
  --text-color: #2c3e50;
  --card-bg: #fff;
}

body.ui-style-13 {
  --primary-color: #16a085;
  --secondary-color: #138d75;
  --bg-color: #d1f2eb;
  --text-color: #333;
  --card-bg: #fff;
}

body.ui-style-14 {
  --primary-color: #d35400;
  --secondary-color: #ba4a00;
  --bg-color: #fdebd0;
  --text-color: #333;
  --card-bg: #fff;
}

body.ui-style-15 {
  --primary-color: #2980b9;
  --secondary-color: #21618c;
  --bg-color: #d4e6f1;
  --text-color: #2c3e50;
  --card-bg: #fff;
}

body {
  background: var(--bg-color);
  color: var(--text-color);
  transition: background-color 0.3s ease;
}

a {
  transition: color 0.3s ease;
}

a:hover {
  color: var(--primary-color);
}

nav a:hover {
  background: var(--primary-color);
  color: #fff;
  transform: translateY(-2px);
}

.container section {
  animation: fadeInUp 0.6s ease-out;
}

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

article, .card {
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

article:hover, .card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.15) !important;
}

h1, h2, h3 {
  color: var(--text-color);
}

h1 {
  position: relative;
  display: inline-block;
}

h1::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 60px;
  height: 3px;
  background: var(--primary-color);
}

button, .btn {
  background: var(--primary-color);
  color: #fff;
  border: none;
  padding: 10px 25px;
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.3s ease;
}

button:hover, .btn:hover {
  background: var(--secondary-color);
  transform: scale(1.05);
}

.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background: var(--primary-color);
  color: #fff;
  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 ease;
  font-size: 24px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
  z-index: 999;
}

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

.back-to-top:hover {
  background: var(--secondary-color);
  transform: translateY(-5px);
}

@media (max-width: 768px) {
  .container {
    padding: 20px 15px;
  }

  h1 {
    font-size: 24px !important;
  }

  h2 {
    font-size: 20px !important;
  }

  article, .card {
    padding: 15px !important;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 45px;
    height: 45px;
  }
}

@media (max-width: 480px) {
  nav a {
    font-size: 12px !important;
    padding: 6px 2px !important;
  }

  .logo {
    font-size: 18px !important;
  }
}