:root {
  --primary-color: #03A9F4;
  --secondary-color: #673AB7;
  --accent-color: #FF9800;
  --background-color: #FFFFFF;
  --text-color: #333333;
  --light-gray: #f5f5f5;
  --medium-gray: #e0e0e0;
  --dark-gray: #757575;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Roboto', 'Open Sans', sans-serif;
}

body {
  background-color: var(--background-color);
  color: var(--text-color);
  line-height: 1.6;
  font-size: 16px;
  overflow-x: hidden;
}

.header {
  position: relative;
  height: 500px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: var(--background-color);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: 0 20px;
  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: 0.2;
  z-index: 0;
}

.header-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.header h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
  text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.header p {
  font-size: 1.2rem;
  margin-bottom: 2rem;
}

.notice {
  background-color: rgba(255,255,255,0.2);
  padding: 15px;
  border-radius: 8px;
  margin-top: 30px;
  backdrop-filter: blur(5px);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px 20px;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
  margin-bottom: 50px;
}

.card {
  background: var(--background-color);
  border-radius: 12px;
  box-shadow: 0 10px 20px rgba(0,0,0,0.1);
  padding: 30px;
  transition: all 0.3s ease;
}

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

.card-img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: 8px;
  margin-bottom: 20px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

article {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
}

article h2 {
  font-size: 2rem;
  color: var(--primary-color);
  margin: 40px 0 20px;
  position: relative;
  padding-bottom: 10px;
}

article h2::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100px;
  height: 3px;
  background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
}

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

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

pre {
  background-color: #f8f8f8;
  border-radius: 8px;
  padding: 20px;
  margin: 20px 0;
  overflow: auto;
  box-shadow: inset 0 0 10px rgba(0,0,0,0.1);
}

code {
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
  color: #333;
}

.footer {
  background: linear-gradient(135deg, var(--secondary-color), #4a148c);
  color: white;
  padding: 40px 20px;
  text-align: center;
}

.footer p {
  margin-bottom: 10px;
}

.nav-links {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 20px;
}

.nav-links a {
  color: white;
  text-decoration: none;
  transition: color 0.3s;
}

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

@media (max-width: 768px) {
  .header h1 {
    font-size: 2rem;
  }
  
  .header p {
    font-size: 1rem;
  }
  
  article h2 {
    font-size: 1.5rem;
  }
  
  article h3 {
    font-size: 1.2rem;
  }
  
  .grid {
    grid-template-columns: 1fr;
  }
}

/* Animation */
@keyframes float {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-20px);
  }
}

.floating-img {
  animation: float 6s ease-in-out infinite;
}

/* Decorative elements */
.decorative-line {
  height: 2px;
  background: linear-gradient(to right, transparent, var(--primary-color), transparent);
  margin: 40px 0;
}

.circle-decoration {
  position: absolute;
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(3,169,244,0.1) 0%, rgba(0,0,0,0) 70%);
  z-index: -1;
}

.circle-1 {
  top: 10%;
  left: 10%;
}

.circle-2 {
  bottom: 10%;
  right: 10%;
}