:root {
  --primary: #1e3c72;
  --secondary: #6a11cb;
  --accent: #ff6a00;
  --light: #f8f9fa;
  --dark: #212529;
  --text: #333;
  --gradient: linear-gradient(135deg, var(--primary), var(--secondary));
}

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

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

.aurora-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, #1e3c72, #2a5298, #6a11cb, #2575fc);
  background-size: 400% 400%;
  animation: gradientAnimation 15s ease infinite;
  z-index: -2;
}

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

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

.header {
  position: relative;
  padding: 80px 0 120px;
  text-align: center;
  color: white;
  overflow: hidden;
}

.header::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100px;
  background: linear-gradient(to bottom, transparent, var(--light));
  z-index: -1;
}

.header h1 {
  font-size: 3.5rem;
  margin-bottom: 20px;
  text-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

.header p {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto;
  opacity: 0.9;
}

.nav {
  position: sticky;
  top: 0;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 15px rgba(0,0,0,0.1);
  z-index: 1000;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 0;
}

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

.nav-links a {
  color: var(--dark);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
  position: relative;
}

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

.nav-links a::after {
  content: "";
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s;
}

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

.brand {
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--primary);
}

.main {
  position: relative;
  background: white;
  border-radius: 30px 30px 0 0;
  margin-top: -50px;
  box-shadow: 0 -10px 30px rgba(0,0,0,0.1);
  padding: 60px 0;
  z-index: 1;
}

.section {
  margin-bottom: 80px;
}

.section-header {
  text-align: center;
  margin-bottom: 50px;
}

.section-header h2 {
  font-size: 2.2rem;
  color: var(--primary);
  margin-bottom: 15px;
  position: relative;
  display: inline-block;
}

.section-header h2::after {
  content: "";
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 4px;
  background: var(--gradient);
  border-radius: 2px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 30px;
}

.card {
  background: white;
  border-radius: 15px;
  overflow: hidden;
  box-shadow: 0 10px 30px rgba(0,0,0,0.08);
  transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 40px rgba(0,0,0,0.15);
}

.card-img {
  height: 200px;
  overflow: hidden;
}

.card-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s;
}

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

.card-body {
  padding: 25px;
}

.card-body h3 {
  font-size: 1.4rem;
  margin-bottom: 15px;
  color: var(--primary);
}

.card-body p {
  margin-bottom: 20px;
  color: #666;
}

.btn {
  display: inline-block;
  padding: 10px 25px;
  background: var(--gradient);
  color: white;
  border-radius: 30px;
  text-decoration: none;
  font-weight: 500;
  transition: transform 0.3s, box-shadow 0.3s;
  box-shadow: 0 4px 15px rgba(30, 60, 114, 0.3);
}

.btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(30, 60, 114, 0.4);
}

.code-block {
  background: #1e1e1e;
  border-radius: 10px;
  padding: 20px;
  margin: 30px 0;
  overflow: auto;
}

.code-block pre {
  margin: 0;
  font-family: 'Courier New', monospace;
  color: #f8f8f2;
  line-height: 1.5;
  tab-size: 2;
}

.code-block .keyword {
  color: #569cd6;
}

.code-block .property {
  color: #9cdcfe;
}

.code-block .value {
  color: #ce9178;
}

.code-block .selector {
  color: #d7ba7d;
}

.code-block .comment {
  color: #6a9955;
}

.footer {
  background: var(--dark);
  color: white;
  padding: 50px 0;
  text-align: center;
}

.footer p {
  opacity: 0.7;
  margin-top: 20px;
}

@media (max-width: 768px) {
  .header h1 {
    font-size: 2.5rem;
  }
  
  .nav-container {
    flex-direction: column;
    gap: 15px;
  }
  
  .nav-links {
    gap: 15px;
  }
  
  .card-grid {
    grid-template-columns: 1fr;
  }
}

.notice {
  background: rgba(255,255,255,0.9);
  padding: 15px;
  border-radius: 8px;
  text-align: center;
  margin: 20px 0;
  box-shadow: 0 4px 15px rgba(0,0,0,0.1);
  border-left: 4px solid var(--accent);
}