:root {
  --primary: #1E90FF;
  --secondary: #8A2BE2;
  --accent: #00BFFF;
  --dark: #0A192F;
  --light: #F8F9FA;
  --text: #333333;
  --gradient: linear-gradient(135deg, var(--primary), var(--secondary));
}

body {
  font-family: 'Montserrat', sans-serif;
  line-height: 1.6;
  color: var(--text);
  background-color: var(--light);
  margin: 0;
  padding: 0;
  overflow-x: hidden;
}

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

.header {
  background: var(--gradient);
  color: white;
  padding: 60px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
  margin-bottom: 60px;
}

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

.header h1 {
  font-size: 2.8rem;
  margin: 0;
  position: relative;
  z-index: 1;
  text-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

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

.notice {
  background: rgba(255,255,255,0.9);
  color: var(--dark);
  padding: 15px;
  border-radius: 8px;
  margin: 30px auto;
  max-width: 600px;
  text-align: center;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  font-size: 0.9rem;
}

article {
  background: white;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
  padding: 40px;
  margin-bottom: 60px;
}

article h2 {
  color: var(--primary);
  font-size: 2rem;
  margin-top: 0;
  border-bottom: 2px solid var(--accent);
  padding-bottom: 10px;
  display: inline-block;
}

article h3 {
  color: var(--secondary);
  font-size: 1.5rem;
  margin: 30px 0 15px;
}

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

pre {
  background: var(--dark);
  color: white;
  padding: 20px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 25px 0;
  font-family: 'Courier New', monospace;
  font-size: 0.95rem;
  line-height: 1.5;
  box-shadow: 0 4px 6px rgba(0,0,0,0.2);
}

code {
  font-family: 'Courier New', monospace;
  background: rgba(30, 144, 255, 0.1);
  padding: 2px 5px;
  border-radius: 3px;
  color: var(--primary);
}

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

.image-card {
  background: white;
  border-radius: 12px;
  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(-5px);
  box-shadow: 0 10px 25px rgba(0,0,0,0.15);
}

.image-card img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 12px 12px 0 0;
}

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

.nav-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 30px 0;
  justify-content: center;
}

.nav-tab {
  padding: 10px 20px;
  background: white;
  border-radius: 30px;
  color: var(--primary);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.nav-tab:hover {
  background: var(--primary);
  color: white;
  transform: translateY(-2px);
}

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

.footer p {
  margin: 0;
  opacity: 0.8;
}

@media (max-width: 768px) {
  .header h1 {
    font-size: 2rem;
  }
  
  article {
    padding: 25px;
  }
  
  article h2 {
    font-size: 1.8rem;
  }
  
  article h3 {
    font-size: 1.3rem;
  }
}

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

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

.highlight-box {
  background: linear-gradient(135deg, rgba(30, 144, 255, 0.1), rgba(138, 43, 226, 0.1));
  border-left: 4px solid var(--primary);
  padding: 20px;
  margin: 30px 0;
  border-radius: 0 8px 8px 0;
}

.highlight-box h4 {
  color: var(--secondary);
  margin-top: 0;
}

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

.tooltip .tooltiptext {
  visibility: hidden;
  width: 200px;
  background-color: var(--dark);
  color: #fff;
  text-align: center;
  border-radius: 6px;
  padding: 5px;
  position: absolute;
  z-index: 1;
  bottom: 125%;
  left: 50%;
  margin-left: -100px;
  opacity: 0;
  transition: opacity 0.3s;
}

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