:root {
  --primary: linear-gradient(135deg, #A897F3, #8DC6FF);
  --secondary: #EDEDED;
  --accent: #8DC6FF;
  --text: #333;
  --light: #F5F5F5;
  --shadow: 0 4px 20px rgba(0,0,0,0.1);
  --radius: 12px;
  --transition: all 0.3s ease;
}

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

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

.header-banner {
  background: var(--primary);
  padding: 2rem;
  text-align: center;
  color: white;
  margin-bottom: 3rem;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}

.header-banner::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('https://images.gptkong.com/demo/sample1.png') no-repeat;
  background-size: cover;
  opacity: 0.1;
  z-index: 0;
}

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

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

.notice {
  background: white;
  padding: 1rem;
  border-radius: var(--radius);
  margin: 2rem auto;
  max-width: 800px;
  text-align: center;
  box-shadow: var(--shadow);
  font-size: 0.9rem;
  color: #666;
}

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

.grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 2rem;
  margin-bottom: 3rem;
}

@media (max-width: 1024px) {
  .grid {
    grid-template-columns: repeat(9, 1fr);
  }
}

@media (max-width: 768px) {
  .grid {
    grid-template-columns: repeat(6, 1fr);
  }
}

@media (max-width: 480px) {
  .grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.card {
  background: white;
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow);
  transition: var(--transition);
  grid-column: span 3;
  position: relative;
  overflow: hidden;
  min-height: 400px;
}

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

.card:nth-child(1) {
  grid-column: span 6;
  min-height: 500px;
}

.card-image {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
  transition: var(--transition);
}

.card:hover .card-image {
  transform: scale(1.05);
}

.card h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  color: var(--text);
}

.card p {
  margin-bottom: 1.5rem;
  font-size: 1rem;
}

.code-block {
  background: #282c34;
  color: #abb2bf;
  padding: 1.5rem;
  border-radius: var(--radius);
  margin: 1.5rem 0;
  overflow: auto;
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
  line-height: 1.5;
}

.code-block::-webkit-scrollbar {
  height: 6px;
}

.code-block::-webkit-scrollbar-thumb {
  background: #4d5764;
  border-radius: 3px;
}

.illustration-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin: 2rem 0;
}

.illustration-item {
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.illustration-item:hover {
  transform: scale(1.05);
}

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

.footer {
  background: var(--secondary);
  padding: 2rem;
  text-align: center;
  margin-top: 3rem;
}

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

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

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

.nav-link {
  color: var(--text);
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
}

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

.hamburger {
  display: none;
  flex-direction: column;
  cursor: pointer;
}

.hamburger span {
  width: 25px;
  height: 3px;
  background: var(--text);
  margin: 3px 0;
  transition: var(--transition);
}

@media (max-width: 768px) {
  .nav-menu {
    display: none;
  }
  .hamburger {
    display: flex;
  }
}

.content-section {
  padding: 6rem 0 3rem;
}

.section-title {
  font-size: 2rem;
  margin-bottom: 2rem;
  position: relative;
  padding-bottom: 1rem;
  color: var(--text);
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100px;
  height: 4px;
  background: var(--primary);
  border-radius: 2px;
}

.tech-demo {
  background: white;
  padding: 2rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin: 2rem 0;
}

.chart-container {
  display: flex;
  justify-content: space-around;
  flex-wrap: wrap;
  margin: 2rem 0;
}

.chart {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background: conic-gradient(var(--accent) 0% 70%, #A897F3 70% 100%);
  position: relative;
  margin: 1rem;
  animation: rotate 5s linear infinite;
}

@keyframes rotate {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.button {
  display: inline-block;
  background: var(--accent);
  color: white;
  padding: 0.8rem 1.5rem;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
  border: none;
  cursor: pointer;
  margin: 0.5rem;
}

.button:hover {
  background: #A897F3;
  transform: translateY(-3px);
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.button:active {
  transform: translateY(0);
}

.fade-in {
  animation: fadeIn 1s ease-in;
}

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

.expandable {
  margin: 1.5rem 0;
}

.expandable-title {
  background: var(--secondary);
  padding: 1rem;
  border-radius: var(--radius);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 500;
}

.expandable-content {
  padding: 1rem;
  background: white;
  border-radius: 0 0 var(--radius) var(--radius);
  display: none;
}

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

.tooltip {
  position: relative;
  display: inline-block;
}

.tooltip-text {
  visibility: hidden;
  width: 200px;
  background: var(--text);
  color: white;
  text-align: center;
  border-radius: var(--radius);
  padding: 0.5rem;
  position: absolute;
  z-index: 1;
  bottom: 125%;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
  transition: var(--transition);
}

.tooltip:hover .tooltip-text {
  visibility: visible;
  opacity: 1;
}

.highlight {
  background: linear-gradient(90deg, rgba(168,151,243,0.2), transparent);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
}

.color-swatch {
  display: inline-block;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  vertical-align: middle;
  margin-right: 0.5rem;
  box-shadow: 0 0 0 1px rgba(0,0,0,0.1);
}

@media (max-width: 480px) {
  .header-banner h1 {
    font-size: 1.8rem;
  }
  .card {
    grid-column: span 6;
  }
  .card:nth-child(1) {
    grid-column: span 6;
  }
}