:root {
  --primary: #1E275A;
  --primary-light: #16204B;
  --secondary: #333333;
  --accent: #FF9B00;
  --accent-dark: #e68a00;
  --bg: #F7F7F7;
  --text: #333333;
  --text-light: #666666;
  --white: #FFFFFF;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  --radius: 8px;
  --transition: all 0.3s ease;
}

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

body {
  font-family: 'Roboto', -apple-system, BlinkMacSystemFont, sans-serif;
  line-height: 1.6;
  color: var(--text);
  background-color: var(--bg);
  overflow-x: hidden;
}

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

/* Header Styles */
.header {
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: var(--white);
  padding: 80px 0 120px;
  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/sample3.png') no-repeat;
  background-size: 40%;
  background-position: right bottom;
  opacity: 0.1;
}

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

.header h1 {
  font-size: 3rem;
  margin-bottom: 20px;
  font-weight: 700;
  line-height: 1.2;
}

.header p {
  font-size: 1.2rem;
  margin-bottom: 30px;
  opacity: 0.9;
}

.notice {
  background-color: rgba(255, 255, 255, 0.2);
  padding: 15px;
  border-radius: var(--radius);
  margin-top: 40px;
  font-size: 0.9rem;
  display: inline-block;
}

/* Navigation */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  padding: 20px 0;
  z-index: 1000;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.nav-links {
  display: flex;
  list-style: none;
}

.nav-links li {
  margin-left: 30px;
}

.nav-links a {
  color: var(--white);
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  width: 0;
  height: 2px;
  bottom: -5px;
  left: 0;
  background-color: var(--accent);
  transition: var(--transition);
}

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

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

/* Article Styles */
.article-container {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 40px;
  margin-bottom: 80px;
}

article {
  background-color: var(--white);
  padding: 40px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

article h2 {
  color: var(--primary);
  margin-bottom: 30px;
  font-size: 2rem;
  position: relative;
  padding-bottom: 15px;
}

article h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--primary));
}

article h3 {
  color: var(--primary);
  margin: 40px 0 20px;
  font-size: 1.5rem;
}

article p {
  margin-bottom: 20px;
  color: var(--text-light);
}

/* Code Blocks */
pre {
  background-color: #f8f8f8;
  border-radius: var(--radius);
  padding: 20px;
  margin: 25px 0;
  overflow: auto;
  border-left: 4px solid var(--accent);
}

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

/* Table Styles */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 30px 0;
  box-shadow: 0 2px 3px rgba(0,0,0,0.1);
}

th, td {
  padding: 12px 15px;
  text-align: left;
  border-bottom: 1px solid #ddd;
}

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

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

tr:hover {
  background-color: #f1f1f1;
}

/* Sidebar */
.sidebar {
  position: sticky;
  top: 100px;
  align-self: start;
}

.sidebar-section {
  background-color: var(--white);
  padding: 25px;
  border-radius: var(--radius);
  margin-bottom: 30px;
  box-shadow: var(--shadow);
}

.sidebar-title {
  color: var(--primary);
  margin-bottom: 20px;
  font-size: 1.2rem;
  position: relative;
  padding-bottom: 10px;
}

.sidebar-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 40px;
  height: 2px;
  background-color: var(--accent);
}

.sidebar-img-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 15px;
  margin-top: 20px;
}

.sidebar-img {
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 3px 10px rgba(0,0,0,0.1);
  transition: var(--transition);
}

.sidebar-img:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.15);
}

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

/* Buttons & Links */
.button {
  display: inline-block;
  background-color: var(--accent);
  color: var(--white);
  padding: 12px 25px;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.button:hover {
  background-color: var(--accent-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(0,0,0,0.15);
}

.link {
  color: var(--primary);
  text-decoration: none;
  position: relative;
  transition: var(--transition);
}

.link::after {
  content: '';
  position: absolute;
  width: 0;
  height: 2px;
  bottom: -2px;
  left: 0;
  background-color: var(--accent);
  transition: var(--transition);
}

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

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

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

/* Responsive Design */
@media (max-width: 992px) {
  .article-container {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    position: static;
    margin-top: 50px;
  }
}

@media (max-width: 768px) {
  .header h1 {
    font-size: 2.2rem;
  }
  
  .header p {
    font-size: 1rem;
  }
  
  .nav-links li {
    margin-left: 15px;
  }
  
  article {
    padding: 30px;
  }
}

@media (max-width: 576px) {
  .header {
    padding: 60px 0 80px;
  }
  
  .nav-container {
    flex-direction: column;
  }
  
  .nav-links {
    margin-top: 15px;
  }
  
  .nav-links li {
    margin-left: 10px;
    margin-right: 10px;
  }
  
  article {
    padding: 20px;
  }
  
  .sidebar-img-grid {
    grid-template-columns: 1fr;
  }
}