:root {
  --primary: #2D9CDB;
  --secondary: #9B51E0;
  --accent1: #F2994A;
  --accent2: #27AE60;
  --dark: #1A1A2E;
  --light: #F5F7FA;
  --gray: #E0E5EC;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Roboto', sans-serif;
  line-height: 1.6;
  color: #333;
  background: var(--light);
  overflow-x: hidden;
}

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

/* Header Styles */
.header {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  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') no-repeat center/cover;
  opacity: 0.1;
  z-index: 0;
}

.header-content {
  position: relative;
  z-index: 1;
}

.header h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  text-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.header p {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto;
}

.notice {
  background: rgba(255,255,255,0.2);
  padding: 10px;
  border-radius: 4px;
  margin-top: 1rem;
  display: inline-block;
  font-size: 0.9rem;
}

/* Navigation */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(255,255,255,0.95);
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
  z-index: 1000;
  transition: all 0.3s ease;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
}

.nav-logo {
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  font-size: 1.2rem;
}

.nav-links {
  display: flex;
  gap: 2rem;
}

.nav-link {
  color: var(--dark);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s ease;
  position: relative;
}

.nav-link:hover {
  color: var(--primary);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: width 0.3s ease;
}

.nav-link:hover::after {
  width: 100%;
}

/* Article Styles */
article {
  margin: 4rem 0;
  background: white;
  border-radius: 10px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.05);
  overflow: hidden;
  padding: 3rem;
}

article h2 {
  color: var(--primary);
  font-size: 2rem;
  margin-bottom: 2rem;
  text-align: center;
  position: relative;
  padding-bottom: 1rem;
}

article h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100px;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
}

section {
  margin-bottom: 3rem;
  padding: 2rem;
  background: rgba(245,247,250,0.5);
  border-radius: 8px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

section:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}

section h3 {
  color: var(--secondary);
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
}

section h3::before {
  content: '';
  display: inline-block;
  width: 20px;
  height: 20px;
  background: var(--accent1);
  margin-right: 10px;
  border-radius: 50%;
}

p {
  margin-bottom: 1.5rem;
  font-size: 1.1rem;
  line-height: 1.8;
}

/* Code Blocks */
pre {
  background: var(--dark);
  color: white;
  padding: 1.5rem;
  border-radius: 8px;
  overflow-x: auto;
  margin: 2rem 0;
  position: relative;
}

pre::before {
  content: 'CSS';
  position: absolute;
  top: 0;
  left: 0;
  background: var(--primary);
  color: white;
  padding: 0.2rem 0.8rem;
  border-radius: 0 0 4px 0;
  font-size: 0.8rem;
}

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

/* Images */
.img-container {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  margin: 2rem 0;
  justify-content: center;
}

.img-box {
  width: 300px;
  height: 300px;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
  transition: transform 0.3s ease;
}

.img-box:hover {
  transform: scale(1.05);
}

.img-box img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* Table Styles */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  background: white;
  box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

th, td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid var(--gray);
}

th {
  background: var(--primary);
  color: white;
  font-weight: 500;
}

tr:nth-child(even) {
  background: rgba(45,156,219,0.05);
}

/* Footer */
.footer {
  background: var(--dark);
  color: white;
  padding: 3rem 0;
  text-align: center;
  margin-top: 5rem;
}

.footer p {
  margin-bottom: 0;
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideUp {
  from {
    transform: translateY(50px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

.animate {
  animation: fadeIn 1s ease forwards;
}

.section-animate {
  animation: slideUp 0.8s ease forwards;
}

/* Responsive */
@media (max-width: 768px) {
  .nav-container {
    flex-direction: column;
    gap: 1rem;
  }
  
  .nav-links {
    gap: 1rem;
  }
  
  article {
    padding: 2rem 1rem;
  }
  
  section {
    padding: 1.5rem;
  }
  
  .img-box {
    width: 100%;
  }
}