:root {
  --primary-dark: #0d1b2a;
  --primary-mid: #1b263b;
  --primary-light: #415a77;
  --accent-blue: #00c6ff;
  --accent-purple: #9d4edd;
  --accent-green: #52b788;
  --neutral-light: #f0f0f0;
  --neutral-mid: #778da9;
  --neutral-dark: #333;
  --highlight: #ff4757;
}

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

body {
  background: linear-gradient(135deg, var(--primary-dark), var(--primary-mid), var(--primary-light));
  color: var(--neutral-light);
  font-family: 'Roboto', sans-serif;
  line-height: 1.6;
  padding: 0;
  margin: 0;
  min-height: 100%;
}

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

.header {
  background: rgba(27, 38, 59, 0.9);
  padding: 20px 0;
  position: fixed;
  width: 100%;
  top: 0;
  z-index: 1000;
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
}

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

.logo {
  font-size: 24px;
  font-weight: 700;
  background: linear-gradient(45deg, var(--accent-blue), var(--accent-purple));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  text-decoration: none;
}

.nav {
  display: flex;
  gap: 30px;
}

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

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

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

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

.notification {
  position: relative;
}

.notification::after {
  content: '';
  position: absolute;
  top: -5px;
  right: -5px;
  width: 10px;
  height: 10px;
  background: var(--highlight);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.5); opacity: 0.5; }
  100% { transform: scale(1); opacity: 1; }
}

.hero {
  padding: 180px 0 100px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::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: -1;
}

.hero-title {
  font-size: 48px;
  margin-bottom: 20px;
  background: linear-gradient(45deg, var(--accent-blue), var(--accent-purple), var(--accent-green));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: gradientShift 8s ease infinite;
  background-size: 200% 200%;
}

@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.hero-subtitle {
  font-size: 20px;
  color: var(--neutral-mid);
  max-width: 700px;
  margin: 0 auto 40px;
}

.hero-cta {
  display: inline-block;
  padding: 15px 30px;
  background: linear-gradient(45deg, var(--accent-blue), var(--accent-purple));
  color: white;
  text-decoration: none;
  border-radius: 50px;
  font-weight: 600;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  box-shadow: 0 4px 15px rgba(0, 198, 255, 0.3);
}

.hero-cta:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(0, 198, 255, 0.4);
}

.content-section {
  padding: 80px 0;
}

.section-title {
  font-size: 36px;
  margin-bottom: 50px;
  text-align: center;
  position: relative;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -15px;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
}

.grid-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: 30px;
  margin-bottom: 60px;
}

.card {
  background: rgba(27, 38, 59, 0.7);
  border-radius: 15px;
  padding: 30px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  position: relative;
  overflow: hidden;
  border: 1px solid rgba(119, 141, 169, 0.2);
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, rgba(0, 198, 255, 0.1), rgba(157, 78, 221, 0.1));
  z-index: -1;
}

.card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.3);
}

.card-img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: 10px;
  margin-bottom: 20px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
  transition: transform 0.3s ease;
}

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

.card-title {
  font-size: 22px;
  margin-bottom: 15px;
  color: var(--accent-blue);
}

.card-text {
  color: var(--neutral-mid);
  margin-bottom: 20px;
}

.card-date {
  color: var(--accent-green);
  font-size: 14px;
  font-weight: 500;
}

.article-container {
  background: rgba(27, 38, 59, 0.7);
  border-radius: 15px;
  padding: 50px;
  margin: 40px 0;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

article {
  max-width: 900px;
  margin: 0 auto;
}

article h2 {
  font-size: 32px;
  margin: 40px 0 20px;
  color: var(--accent-blue);
  position: relative;
  padding-bottom: 10px;
}

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

article h3 {
  font-size: 26px;
  margin: 30px 0 15px;
  color: var(--accent-purple);
}

article p {
  margin-bottom: 20px;
  font-size: 17px;
  line-height: 1.7;
}

pre {
  background: rgba(13, 27, 42, 0.8);
  border-radius: 10px;
  padding: 20px;
  margin: 25px 0;
  overflow-x: auto;
  border-left: 4px solid var(--accent-blue);
  box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.3);
}

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

table {
  width: 100%;
  border-collapse: collapse;
  margin: 25px 0;
  background: rgba(27, 38, 59, 0.7);
  border-radius: 10px;
  overflow: hidden;
}

th, td {
  padding: 15px;
  text-align: left;
  border-bottom: 1px solid rgba(119, 141, 169, 0.3);
}

th {
  background: rgba(0, 198, 255, 0.1);
  color: var(--accent-blue);
  font-weight: 600;
}

tr:hover {
  background: rgba(0, 198, 255, 0.05);
}

.footer {
  background: rgba(13, 27, 42, 0.9);
  padding: 50px 0 20px;
  text-align: center;
  margin-top: 80px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 30px;
  margin-bottom: 30px;
}

.footer-link {
  color: var(--neutral-mid);
  text-decoration: none;
  transition: color 0.3s ease;
}

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

.copyright {
  color: var(--neutral-mid);
  font-size: 14px;
  margin-top: 30px;
}

.reference {
  background: rgba(255, 71, 87, 0.1);
  padding: 15px;
  border-radius: 10px;
  margin: 30px 0;
  text-align: center;
  border: 1px solid rgba(255, 71, 87, 0.3);
  color: var(--neutral-light);
}

@media (max-width: 768px) {
  .header-container {
    flex-direction: column;
    gap: 20px;
  }
  
  .nav {
    gap: 15px;
  }
  
  .hero {
    padding: 150px 0 80px;
  }
  
  .hero-title {
    font-size: 36px;
  }
  
  .grid-container {
    grid-template-columns: 1fr;
  }
  
  .article-container {
    padding: 30px;
  }
  
  article h2 {
    font-size: 28px;
  }
  
  article h3 {
    font-size: 22px;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 28px;
  }
  
  .hero-subtitle {
    font-size: 16px;
  }
  
  .section-title {
    font-size: 28px;
  }
  
  .card {
    padding: 20px;
  }
  
  .footer-links {
    flex-direction: column;
    gap: 15px;
  }
}

/* 3D Card Flip Effect */
.card-3d {
  perspective: 1000px;
  height: 300px;
}

.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.8s;
  transform-style: preserve-3d;
}

.card-3d:hover .card-inner {
  transform: rotateY(180deg);
}

.card-front, .card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 15px;
  padding: 30px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.card-front {
  background: linear-gradient(135deg, var(--primary-mid), var(--primary-light));
}

.card-back {
  background: linear-gradient(135deg, var(--primary-light), var(--primary-mid));
  transform: rotateY(180deg);
}

/* Parallax Effect */
.parallax-section {
  height: 400px;
  background-attachment: fixed;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
  position: relative;
  margin: 80px 0;
}

.parallax-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(13, 27, 42, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  text-align: center;
  padding: 0 20px;
}

/* Floating Animation */
@keyframes float {
  0% { transform: translateY(0px); }
  50% { transform: translateY(-20px); }
  100% { transform: translateY(0px); }
}

.floating {
  animation: float 6s ease-in-out infinite;
}

/* Glow Effect */
.glow {
  text-shadow: 0 0 10px rgba(0, 198, 255, 0.7);
}

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

.tooltip .tooltiptext {
  visibility: hidden;
  width: 200px;
  background-color: var(--primary-dark);
  color: var(--neutral-light);
  text-align: center;
  border-radius: 6px;
  padding: 10px;
  position: absolute;
  z-index: 1;
  bottom: 125%;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
  transition: opacity 0.3s;
}

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

/* Responsive Images */
.responsive-img {
  max-width: 100%;
  height: auto;
  border-radius: 10px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
  margin: 20px 0;
  transition: transform 0.3s ease;
}

.responsive-img:hover {
  transform: scale(1.02);
}