:root {
  --primary-dark: #1A237E;
  --primary-light: #673AB7;
  --accent-green: #4CAF50;
  --accent-orange: #FF9800;
  --text-dark: #333;
  --text-light: #f5f5f5;
  --bg-light: #f8f9fa;
  --shadow-sm: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 10px 20px rgba(0, 0, 0, 0.15);
}

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

body {
  background-color: var(--bg-light);
  color: var(--text-dark);
  line-height: 1.6;
  overflow-x: hidden;
}

header {
  background: linear-gradient(135deg, var(--primary-dark), var(--primary-light));
  color: white;
  padding: 2rem 0;
  text-align: center;
  position: relative;
  overflow: hidden;
  margin-bottom: 3rem;
}

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-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);
}

.tagline {
  font-size: 1.2rem;
  opacity: 0.9;
  margin-bottom: 1.5rem;
}

.notice {
  background-color: rgba(255, 255, 255, 0.2);
  padding: 0.8rem;
  border-radius: 8px;
  display: inline-block;
  margin-top: 1rem;
  font-size: 0.9rem;
  backdrop-filter: blur(5px);
}

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

article {
  background-color: white;
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
  padding: 3rem;
  margin-bottom: 3rem;
  position: relative;
  overflow: hidden;
}

article::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 150px;
  height: 150px;
  background: url('https://images.gptkong.com/demo/sample3.png') center/cover no-repeat;
  opacity: 0.1;
  z-index: 0;
}

h2, h3, h4 {
  color: var(--primary-dark);
  margin: 2rem 0 1rem;
  position: relative;
}

h2 {
  font-size: 1.8rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--primary-light);
}

h3 {
  font-size: 1.5rem;
}

h4 {
  font-size: 1.3rem;
}

p {
  margin-bottom: 1.2rem;
  font-size: 1.05rem;
}

.color-sample {
  display: inline-block;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  margin-right: 5px;
  vertical-align: middle;
}

pre {
  background: linear-gradient(to right, #f5f5f5, #e9e9e9);
  border-left: 4px solid var(--accent-green);
  border-radius: 0 6px 6px 0;
  padding: 1.5rem;
  margin: 1.5rem 0;
  overflow: auto;
  font-family: 'Courier New', monospace;
  font-size: 0.95rem;
  line-height: 1.5;
  position: relative;
}

code {
  background-color: rgba(76, 175, 80, 0.1);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
  color: var(--primary-dark);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  box-shadow: var(--shadow-sm);
  border-radius: 8px;
  overflow: hidden;
}

th, td {
  padding: 0.8rem 1rem;
  text-align: left;
  border-bottom: 1px solid #eee;
}

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

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

ol, ul {
  margin: 1.5rem 0;
  padding-left: 2rem;
}

li {
  margin-bottom: 0.8rem;
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

.image-card {
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.image-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
}

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

.accordion {
  margin: 1.5rem 0;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.accordion-header {
  background: linear-gradient(to right, var(--primary-dark), var(--primary-light));
  color: white;
  padding: 1rem 1.5rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.3s ease;
}

.accordion-header:hover {
  background: linear-gradient(to right, var(--primary-light), var(--primary-dark));
}

.accordion-content {
  padding: 1.5rem;
  background-color: white;
  display: none;
}

.accordion.active .accordion-content {
  display: block;
}

.nav-tabs {
  display: flex;
  margin: 2rem 0;
  border-bottom: 2px solid #eee;
}

.nav-tab {
  padding: 0.8rem 1.5rem;
  cursor: pointer;
  border-bottom: 3px solid transparent;
  transition: all 0.3s ease;
}

.nav-tab.active {
  color: var(--accent-green);
  border-bottom-color: var(--accent-green);
  font-weight: bold;
}

.nav-tab:hover:not(.active) {
  color: var(--primary-light);
  border-bottom-color: #ddd;
}

@media (max-width: 768px) {
  article {
    padding: 2rem 1.5rem;
  }
  
  .image-grid {
    grid-template-columns: 1fr;
  }
  
  pre {
    padding: 1rem;
    font-size: 0.85rem;
  }
}

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

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

.decorative-element {
  position: absolute;
  width: 100px;
  height: 100px;
  background: url('https://images.gptkong.com/demo/sample5.png') center/cover no-repeat;
  opacity: 0.2;
  z-index: 0;
}

.decorative-element-1 {
  top: 20%;
  left: 5%;
}

.decorative-element-2 {
  bottom: 10%;
  right: 5%;
}