:root {
  --primary: #0D47A1;
  --secondary: #BBDEFB;
  --accent: #FFC107;
  --dark: #1A237E;
  --light: #F5F5F5;
  --text: #333333;
  --white: #FFFFFF;
}

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

body {
  font-family: 'Roboto', sans-serif;
  color: var(--text);
  background: linear-gradient(135deg, var(--light) 0%, var(--white) 100%);
  line-height: 1.6;
  overflow-x: hidden;
}

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

.header {
  background: linear-gradient(90deg, var(--primary) 0%, var(--dark) 100%);
  color: var(--white);
  padding: 2rem 0;
  text-align: center;
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
  position: relative;
  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: 0.1;
  z-index: 0;
}

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

.header p {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.navbar {
  position: sticky;
  top: 0;
  background: var(--white);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  z-index: 1000;
  padding: 1rem 0;
}

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

.nav-logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--primary);
  text-decoration: none;
}

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

.nav-item {
  margin-left: 2rem;
}

.nav-link {
  color: var(--text);
  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(--accent);
  transition: width 0.3s ease;
}

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

.main {
  padding: 3rem 0;
}

.section {
  margin-bottom: 4rem;
  background: var(--white);
  border-radius: 10px;
  padding: 2rem;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.section:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

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

.section h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 50px;
  height: 3px;
  background: var(--accent);
}

.section h3 {
  color: var(--dark);
  margin: 1.5rem 0 1rem;
  font-size: 1.4rem;
}

.section p {
  margin-bottom: 1rem;
  font-size: 1.1rem;
}

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

.card {
  background: var(--white);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.1);
  transition: all 0.3s ease;
  position: relative;
}

.card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
}

.card-img {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.card-content {
  padding: 1.5rem;
}

.card-title {
  font-size: 1.3rem;
  margin-bottom: 0.5rem;
  color: var(--primary);
}

.card-text {
  color: var(--text);
  margin-bottom: 1rem;
}

.code-container {
  background: #282c34;
  border-radius: 8px;
  padding: 1.5rem;
  margin: 2rem 0;
  overflow: hidden;
  position: relative;
}

.code-container::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 30px;
  background: #1e2229;
  border-radius: 8px 8px 0 0;
}

.code-container pre {
  margin: 0;
  overflow-x: auto;
}

.code-container code {
  font-family: 'Courier New', monospace;
  color: #abb2bf;
  font-size: 0.9rem;
  line-height: 1.5;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  background: var(--white);
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.05);
  border-radius: 8px;
  overflow: hidden;
}

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

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

tr:hover {
  background-color: rgba(0, 0, 0, 0.02);
}

.footer {
  background: linear-gradient(90deg, var(--primary) 0%, var(--dark) 100%);
  color: var(--white);
  padding: 3rem 0;
  text-align: center;
}

.footer p {
  margin-bottom: 1rem;
}

.notice {
  background: var(--accent);
  color: var(--white);
  padding: 1rem;
  text-align: center;
  font-weight: bold;
  margin-bottom: 2rem;
  border-radius: 5px;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.1);
}

@media (max-width: 768px) {
  .nav-container {
    flex-direction: column;
  }
  
  .nav-menu {
    margin-top: 1rem;
  }
  
  .nav-item {
    margin-left: 1rem;
    margin-right: 1rem;
  }
  
  .header h1 {
    font-size: 2rem;
  }
  
  .section {
    padding: 1.5rem;
  }
}

@media (max-width: 480px) {
  .grid {
    grid-template-columns: 1fr;
  }
  
  .nav-menu {
    flex-direction: column;
    align-items: center;
  }
  
  .nav-item {
    margin: 0.5rem 0;
  }
  
  .header h1 {
    font-size: 1.8rem;
  }
  
  .section h2 {
    font-size: 1.5rem;
  }
  
  .section h3 {
    font-size: 1.2rem;
  }
}

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

.section {
  animation: fadeIn 0.6s ease forwards;
}

.section:nth-child(2) { animation-delay: 0.1s; }
.section:nth-child(3) { animation-delay: 0.2s; }
.section:nth-child(4) { animation-delay: 0.3s; }
.section:nth-child(5) { animation-delay: 0.4s; }
.section:nth-child(6) { animation-delay: 0.5s; }
.section:nth-child(7) { animation-delay: 0.6s; }
.section:nth-child(8) { animation-delay: 0.7s; }
.section:nth-child(9) { animation-delay: 0.8s; }

/* Button styles */
.button {
  display: inline-block;
  background: linear-gradient(45deg, var(--primary), var(--dark));
  color: var(--white);
  padding: 0.8rem 1.5rem;
  border: none;
  border-radius: 5px;
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.button:hover {
  background: linear-gradient(45deg, var(--dark), var(--primary));
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.button.accent {
  background: linear-gradient(45deg, var(--accent), #FF5722);
}

.button.accent:hover {
  background: linear-gradient(45deg, #FF5722, var(--accent));
}

/* Image decorations */
.decorative-image {
  border-radius: 10px;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  margin: 1rem 0;
  max-width: 100%;
}

.decorative-image:hover {
  transform: scale(1.02);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.2);
}

/* Floating elements */
.floating {
  animation: floating 3s ease-in-out infinite;
}

@keyframes floating {
  0% { transform: translateY(0px); }
  50% { transform: translateY(-15px); }
  100% { transform: translateY(0px); }
}

/* Tooltip */
.tooltip {
  position: relative;
  display: inline-block;
  border-bottom: 1px dotted var(--text);
  cursor: help;
}

.tooltip .tooltiptext {
  visibility: hidden;
  width: 200px;
  background-color: var(--dark);
  color: var(--white);
  text-align: center;
  border-radius: 6px;
  padding: 5px;
  position: absolute;
  z-index: 1;
  bottom: 125%;
  left: 50%;
  margin-left: -100px;
  opacity: 0;
  transition: opacity 0.3s;
}

.tooltip:hover .tooltiptext {
  visibility: visible;
  opacity: 1;
}