:root {
  --primary: #0f2027;
  --secondary: #203a43;
  --accent: #00e6e6;
  --text: #ffffff;
  --highlight: #1e90ff;
  --bg-gradient: linear-gradient(135deg, var(--primary), var(--secondary), #2c5364);
}

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

body {
  background: var(--bg-gradient);
  color: var(--text);
  font-family: 'Roboto', sans-serif;
  line-height: 1.6;
  padding: 0;
  margin: 0;
  min-height: 100%;
}

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

header {
  text-align: center;
  padding: 40px 0;
  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;
  opacity: 0.2;
  z-index: -1;
}

h1, h2, h3, h4 {
  font-family: 'Montserrat', sans-serif;
  margin-bottom: 20px;
  font-weight: 600;
}

h1 {
  font-size: 2.5rem;
  background: linear-gradient(90deg, var(--accent), var(--highlight));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  text-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

h2 {
  font-size: 1.9rem;
  color: var(--accent);
  position: relative;
  padding-bottom: 10px;
}

h2::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100px;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), transparent);
}

h3 {
  font-size: 1.6rem;
  color: var(--highlight);
  margin-top: 30px;
}

p {
  margin-bottom: 20px;
  font-size: 1.1rem;
}

article {
  background: rgba(32, 58, 67, 0.7);
  backdrop-filter: blur(10px);
  border-radius: 15px;
  padding: 30px;
  margin: 30px 0;
  box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
  margin: 40px 0;
}

.card {
  background: rgba(15, 32, 39, 0.6);
  border-radius: 10px;
  padding: 20px;
  transition: transform 0.3s, box-shadow 0.3s;
  border: 1px solid rgba(0, 230, 230, 0.2);
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 30px rgba(0,0,0,0.4);
}

.img-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 20px;
  margin: 30px 0;
}

.img-box {
  width: 150px;
  height: 150px;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0,0,0,0.2);
  transition: transform 0.3s;
}

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

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

pre {
  background: rgba(15, 32, 39, 0.8);
  border-radius: 8px;
  padding: 20px;
  margin: 20px 0;
  overflow-x: auto;
  border-left: 4px solid var(--accent);
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
  line-height: 1.5;
  position: relative;
}

code {
  color: var(--accent);
  font-family: 'Courier New', monospace;
}

.table {
  width: 100%;
  border-collapse: collapse;
  margin: 30px 0;
  background: rgba(15, 32, 39, 0.6);
  border-radius: 10px;
  overflow: hidden;
}

.table thead {
  background: rgba(0, 230, 230, 0.2);
}

.table th {
  padding: 15px;
  text-align: left;
  color: var(--accent);
  font-weight: 600;
}

.table td {
  padding: 15px;
  border-bottom: 1px solid rgba(0, 230, 230, 0.1);
}

.table tbody tr:hover {
  background: rgba(0, 230, 230, 0.1);
}

.note {
  background: rgba(0, 230, 230, 0.1);
  border-left: 4px solid var(--accent);
  padding: 15px;
  margin: 20px 0;
  border-radius: 0 8px 8px 0;
}

.note p {
  margin: 0;
}

footer {
  text-align: center;
  padding: 30px;
  margin-top: 50px;
  border-top: 1px solid rgba(0, 230, 230, 0.2);
}

@media (max-width: 768px) {
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.6rem;
  }
  
  h3 {
    font-size: 1.3rem;
  }
  
  .grid {
    grid-template-columns: 1fr;
  }
}

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

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

.nav-tabs {
  display: flex;
  justify-content: center;
  margin: 30px 0;
  flex-wrap: wrap;
}

.nav-tabs a {
  color: var(--text);
  text-decoration: none;
  padding: 10px 20px;
  margin: 0 10px;
  border-radius: 30px;
  background: rgba(0, 230, 230, 0.1);
  transition: all 0.3s;
}

.nav-tabs a:hover {
  background: var(--accent);
  color: var(--primary);
  transform: translateY(-3px);
}

.reference-note {
  background: rgba(255,255,255,0.1);
  padding: 15px;
  border-radius: 8px;
  margin: 20px 0;
  text-align: center;
  font-style: italic;
}