:root {
  --retro-beige: #f5f5dc;
  --olive-green: #808000;
  --neon-blue: #1f51ff;
  --bright-purple: #bf00ff;
  --deep-brown: #654321;
  --pure-white: #ffffff;
  --dark-gray: #333333;
  --light-gray: #f8f8f8;
}

@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:wght@400;700&family=Open+Sans:wght@300;400;600&display=swap');

body {
  font-family: 'Open Sans', sans-serif;
  margin: 0;
  padding: 0;
  background-color: var(--light-gray);
  color: var(--dark-gray);
  line-height: 1.6;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.header {
  background: linear-gradient(135deg, var(--deep-brown), var(--olive-green));
  color: var(--pure-white);
  padding: 100px 0;
  text-align: center;
  margin-bottom: 60px;
  position: relative;
  overflow: hidden;
}

.header::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('https://images.gptkong.com/demo/sample1.png') center/cover no-repeat;
  opacity: 0.1;
  z-index: 0;
}

.header h1 {
  font-family: 'Playfair Display', serif;
  font-size: 3rem;
  margin: 0;
  position: relative;
  z-index: 1;
  text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.header p {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 20px auto 0;
  position: relative;
  z-index: 1;
}

.note {
  background-color: var(--retro-beige);
  padding: 15px;
  border-left: 5px solid var(--neon-blue);
  margin: 30px 0;
  font-style: italic;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  background-color: var(--deep-brown);
  color: var(--pure-white);
  display: flex;
  justify-content: center;
  padding: 15px 0;
  box-shadow: 0 2px 10px rgba(0,0,0,0.3);
  z-index: 1000;
}

.navbar a {
  color: var(--pure-white);
  text-decoration: none;
  font-family: 'Open Sans', sans-serif;
  padding: 10px 20px;
  margin: 0 10px;
  border-radius: 5px;
  transition: all 0.3s ease;
  position: relative;
}

.navbar a::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 2px;
  background-color: var(--neon-blue);
  transition: width 0.3s ease;
}

.navbar a:hover::after {
  width: 80%;
}

.navbar a:hover {
  color: var(--neon-blue);
}

.content {
  padding-top: 80px;
}

article {
  background-color: var(--pure-white);
  padding: 40px;
  border-radius: 15px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
  margin-bottom: 60px;
}

article h2 {
  font-family: 'Playfair Display', serif;
  color: var(--olive-green);
  font-size: 2rem;
  margin-top: 40px;
  position: relative;
  padding-bottom: 10px;
}

article h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100px;
  height: 3px;
  background: linear-gradient(90deg, var(--neon-blue), var(--bright-purple));
}

article h3 {
  font-family: 'Playfair Display', serif;
  color: var(--olive-green);
  font-size: 1.5rem;
  margin-top: 30px;
}

article p {
  margin: 20px 0;
  font-size: 1.1rem;
}

article strong {
  color: var(--neon-blue);
}

pre {
  background-color: #282c34;
  color: #abb2bf;
  padding: 20px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 25px 0;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  position: relative;
}

pre::before {
  content: 'CSS';
  position: absolute;
  top: 0;
  left: 0;
  background-color: var(--neon-blue);
  color: white;
  padding: 2px 10px;
  border-radius: 0 0 5px 0;
  font-size: 0.8rem;
}

code {
  font-family: 'Courier New', monospace;
  font-size: 0.95rem;
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin: 40px 0;
}

.image-card {
  background-color: var(--pure-white);
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.image-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 30px rgba(0,0,0,0.2);
}

.image-card img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 10px 10px 0 0;
}

.image-caption {
  padding: 15px;
  background-color: var(--retro-beige);
  text-align: center;
}

.footer {
  background-color: var(--deep-brown);
  color: var(--pure-white);
  padding: 40px 0;
  text-align: center;
  margin-top: 60px;
}

.footer p {
  margin: 0;
}

@media (max-width: 768px) {
  .header h1 {
    font-size: 2rem;
  }
  
  .header p {
    font-size: 1rem;
  }
  
  .navbar {
    flex-wrap: wrap;
    padding: 10px 0;
  }
  
  .navbar a {
    padding: 8px 15px;
    margin: 5px;
    font-size: 0.9rem;
  }
  
  article {
    padding: 20px;
  }
  
  article h2 {
    font-size: 1.5rem;
  }
  
  article h3 {
    font-size: 1.2rem;
  }
  
  .image-grid {
    grid-template-columns: 1fr;
  }
}

/* Animations */
@keyframes float {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}

.floating {
  animation: float 3s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.7;
  }
}

.pulsing {
  animation: pulse 2s ease-in-out infinite;
}

/* Special elements */
.highlight-box {
  background: linear-gradient(135deg, var(--retro-beige), var(--pure-white));
  border-left: 5px solid var(--neon-blue);
  padding: 20px;
  margin: 30px 0;
  border-radius: 0 8px 8px 0;
  box-shadow: 0 3px 10px rgba(0,0,0,0.1);
}

.quote {
  font-style: italic;
  color: var(--olive-green);
  border-left: 3px solid var(--olive-green);
  padding-left: 20px;
  margin: 30px 0;
  font-size: 1.2rem;
}

.tooltip {
  position: relative;
  display: inline-block;
  border-bottom: 1px dotted var(--neon-blue);
  cursor: help;
}

.tooltip .tooltiptext {
  visibility: hidden;
  width: 200px;
  background-color: var(--deep-brown);
  color: var(--pure-white);
  text-align: center;
  border-radius: 6px;
  padding: 5px;
  position: absolute;
  z-index: 1;
  bottom: 125%;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
  transition: opacity 0.3s;
}

.tooltip:hover .tooltiptext {
  visibility: visible;
  opacity: 1;
}