:root {
  --primary-color: #0D47A1;
  --secondary-color: #00C853;
  --accent-color: #FF6F00;
  --neutral-color: #B0BEC5;
  --background-color: #FFFFFF;
  --text-color: #333;
  --light-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  --strong-shadow: 0 8px 12px rgba(0, 0, 0, 0.2);
}

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

body {
  font-family: 'Roboto', sans-serif;
  background-color: var(--background-color);
  color: var(--text-color);
  line-height: 1.6;
  overflow-x: hidden;
}

.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  background: linear-gradient(135deg, var(--primary-color), #1565C0);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 5%;
  box-shadow: var(--light-shadow);
  z-index: 1000;
}

.navbar .logo {
  color: white;
  font-size: 1.8rem;
  font-weight: bold;
  letter-spacing: 1px;
}

.navbar .nav-links {
  display: flex;
  gap: 30px;
}

.navbar .nav-links a {
  color: white;
  text-decoration: none;
  font-size: 1.1rem;
  transition: all 0.3s ease;
  position: relative;
  padding: 5px 0;
}

.navbar .nav-links a:hover {
  color: var(--secondary-color);
}

.navbar .nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--secondary-color);
  transition: width 0.3s ease;
}

.navbar .nav-links a:hover::after {
  width: 100%;
}

.hero {
  height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(rgba(13, 71, 161, 0.8), rgba(13, 71, 161, 0.8)), 
              url('https://images.gptkong.com/demo/sample1.png');
  background-size: cover;
  background-position: center;
  color: white;
  text-align: center;
  padding: 0 20px;
  margin-top: 70px;
}

.hero-content {
  max-width: 800px;
}

.hero h1 {
  font-size: 3.5rem;
  margin-bottom: 20px;
  animation: fadeInUp 1s ease-out;
}

.hero p {
  font-size: 1.2rem;
  margin-bottom: 30px;
  animation: fadeInUp 1s ease-out 0.2s forwards;
  opacity: 0;
}

.btn {
  display: inline-block;
  background: linear-gradient(45deg, var(--secondary-color), var(--accent-color));
  color: white;
  padding: 12px 30px;
  border-radius: 50px;
  text-decoration: none;
  font-weight: bold;
  transition: all 0.3s ease;
  box-shadow: var(--light-shadow);
  animation: fadeInUp 1s ease-out 0.4s forwards;
  opacity: 0;
}

.btn:hover {
  transform: translateY(-3px);
  box-shadow: var(--strong-shadow);
  background: linear-gradient(45deg, var(--accent-color), var(--secondary-color));
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 80px 5%;
}

.section-title {
  text-align: center;
  font-size: 2.5rem;
  color: var(--primary-color);
  margin-bottom: 50px;
  position: relative;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -15px;
  left: 50%;
  transform: translateX(-50%);
  width: 100px;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
  border-radius: 2px;
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 40px;
  margin-bottom: 80px;
}

.feature-card {
  background: white;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: var(--light-shadow);
  transition: all 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-10px);
  box-shadow: var(--strong-shadow);
}

.feature-img {
  height: 200px;
  overflow: hidden;
}

.feature-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.feature-card:hover .feature-img img {
  transform: scale(1.1);
}

.feature-content {
  padding: 25px;
}

.feature-content h3 {
  font-size: 1.5rem;
  margin-bottom: 15px;
  color: var(--primary-color);
}

.feature-content p {
  color: var(--text-color);
  margin-bottom: 20px;
}

.tech-showcase {
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  padding: 80px 0;
  margin: 80px 0;
}

.tech-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 30px;
}

.tech-item {
  background: white;
  border-radius: 10px;
  padding: 30px;
  text-align: center;
  box-shadow: var(--light-shadow);
  transition: all 0.3s ease;
}

.tech-item:hover {
  transform: translateY(-10px);
  box-shadow: var(--strong-shadow);
}

.tech-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto 20px;
  background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 2rem;
}

.tech-item h3 {
  font-size: 1.3rem;
  margin-bottom: 15px;
  color: var(--primary-color);
}

.code-section {
  background: #f8f9fa;
  border-radius: 10px;
  padding: 40px;
  margin: 60px 0;
  box-shadow: var(--light-shadow);
}

.code-section h2 {
  color: var(--primary-color);
  margin-bottom: 30px;
  font-size: 2rem;
}

pre {
  background: #2d2d2d;
  color: #f8f8f2;
  padding: 20px;
  border-radius: 8px;
  overflow-x: auto;
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
  line-height: 1.5;
  margin-bottom: 30px;
}

pre code {
  display: block;
  white-space: pre;
}

.gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin: 60px 0;
}

.gallery-item {
  border-radius: 10px;
  overflow: hidden;
  box-shadow: var(--light-shadow);
  transition: all 0.3s ease;
  position: relative;
}

.gallery-item:hover {
  transform: translateY(-5px);
  box-shadow: var(--strong-shadow);
}

.gallery-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.gallery-item:hover img {
  transform: scale(1.1);
}

.gallery-caption {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: rgba(0, 0, 0, 0.7);
  color: white;
  padding: 15px;
  transform: translateY(100%);
  transition: transform 0.3s ease;
}

.gallery-item:hover .gallery-caption {
  transform: translateY(0);
}

.footer {
  background: linear-gradient(135deg, var(--primary-color), #0b3d91);
  color: white;
  padding: 60px 0 30px;
  text-align: center;
}

.footer-content {
  max-width: 800px;
  margin: 0 auto;
}

.footer p {
  margin-bottom: 20px;
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin: 30px 0;
}

.social-links a {
  color: white;
  font-size: 1.5rem;
  transition: color 0.3s ease;
}

.social-links a:hover {
  color: var(--secondary-color);
}

.copyright {
  margin-top: 30px;
  font-size: 0.9rem;
  opacity: 0.8;
}

.floating-btn {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 60px;
  height: 60px;
  background: linear-gradient(45deg, var(--accent-color), var(--secondary-color));
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  box-shadow: var(--strong-shadow);
  cursor: pointer;
  transition: all 0.3s ease;
  z-index: 1000;
}

.floating-btn:hover {
  transform: scale(1.1);
  background: linear-gradient(45deg, var(--secondary-color), var(--accent-color));
}

.reference {
  position: fixed;
  bottom: 30px;
  left: 30px;
  background: rgba(255, 255, 255, 0.9);
  padding: 10px 15px;
  border-radius: 5px;
  box-shadow: var(--light-shadow);
  font-size: 0.9rem;
  z-index: 1000;
}

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

@media (max-width: 768px) {
  .navbar .nav-links {
    display: none;
  }
  
  .hero h1 {
    font-size: 2.5rem;
  }
  
  .hero p {
    font-size: 1rem;
  }
  
  .section-title {
    font-size: 2rem;
  }
  
  .features {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 2rem;
  }
  
  .btn {
    padding: 10px 20px;
  }
  
  .tech-grid {
    grid-template-columns: 1fr;
  }
  
  .code-section {
    padding: 20px;
  }
  
  .gallery {
    grid-template-columns: 1fr;
  }
}