:root {
  --primary: #2c3e50;
  --secondary: #8e44ad;
  --accent: #e67e22;
  --light: #ecf0f1;
  --dark: #1a1a1a;
  --gradient: linear-gradient(135deg, var(--primary), var(--secondary));
}

body {
  font-family: 'Roboto', 'Helvetica Neue', Arial, sans-serif;
  line-height: 1.6;
  color: #333;
  background-color: #f9f9f9;
  margin: 0;
  padding: 0;
}

header {
  background: var(--gradient);
  color: white;
  padding: 2rem 0;
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

header::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('https://images.gptkong.com/demo/sample3.png') center/cover no-repeat;
  opacity: 0.15;
  z-index: 0;
}

.header-content {
  position: relative;
  z-index: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.subtitle {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto 2rem;
  opacity: 0.9;
}

.notice {
  background-color: rgba(255,255,255,0.2);
  padding: 1rem;
  border-radius: 8px;
  display: inline-block;
  margin-top: 1rem;
  backdrop-filter: blur(5px);
}

.container {
  max-width: 1200px;
  margin: 3rem auto;
  padding: 0 2rem;
}

article {
  background: white;
  border-radius: 12px;
  box-shadow: 0 6px 18px rgba(0,0,0,0.08);
  padding: 3rem;
  margin-bottom: 3rem;
  position: relative;
  overflow: hidden;
}

article::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 100px;
  height: 100px;
  background: var(--gradient);
  clip-path: polygon(0 0, 100% 0, 100% 100%);
  opacity: 0.05;
}

h2 {
  color: var(--primary);
  font-size: 1.8rem;
  margin-top: 2.5rem;
  margin-bottom: 1.5rem;
  position: relative;
  padding-bottom: 0.5rem;
}

h2::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: var(--gradient);
  border-radius: 3px;
}

p {
  font-size: 1.1rem;
  margin-bottom: 1.5rem;
  color: #444;
}

span {
  color: var(--secondary);
  font-weight: 500;
}

pre {
  background: #f5f7fa;
  border-radius: 8px;
  padding: 1.5rem;
  overflow-x: auto;
  margin: 2rem 0;
  border-left: 4px solid var(--accent);
  box-shadow: inset 0 1px 3px rgba(0,0,0,0.1);
}

code {
  font-family: 'Courier New', monospace;
  background: rgba(230, 126, 34, 0.1);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  color: #d35400;
}

ol, ul {
  padding-left: 2rem;
  margin-bottom: 2rem;
}

li {
  margin-bottom: 0.8rem;
  position: relative;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

th, td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid #eee;
}

th {
  background-color: var(--primary);
  color: white;
}

tr:nth-child(even) {
  background-color: #f9f9f9;
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 2rem;
  margin: 3rem 0;
}

.image-card {
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 4px 12px 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 8px 24px rgba(0,0,0,0.15);
}

.image-card img {
  width: 100%;
  height: auto;
  display: block;
}

.nav-links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1rem;
  margin: 2rem 0;
}

.nav-link {
  padding: 0.8rem 1.5rem;
  background: var(--gradient);
  color: white;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 500;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.nav-link:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(0,0,0,0.15);
}

@media (max-width: 768px) {
  .container {
    padding: 0 1.5rem;
  }
  
  article {
    padding: 2rem 1.5rem;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  .image-grid {
    grid-template-columns: 1fr;
  }
}

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

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