:root {
  --primary: #1e3c72;
  --primary-light: #2a5298;
  --secondary: #ff7e5f;
  --secondary-light: #feb47b;
  --accent: #00f2fe;
  --white: #ffffff;
  --gray: #f5f5f5;
  --dark: #333333;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Open Sans', system-ui, -apple-system, sans-serif;
}

body {
  background: linear-gradient(135deg, #f8f9fa, #e9ecef);
  color: var(--dark);
  line-height: 1.6;
  min-height: 100%;
  padding: 0;
  margin: 0;
}

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

.header {
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: var(--white);
  padding: 2rem 0;
  text-align: center;
  border-radius: 0 0 20px 20px;
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
  margin-bottom: 3rem;
  position: relative;
  overflow: hidden;
}

.header::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 70% 30%, rgba(255,255,255,0.1) 0%, transparent 50%);
}

.header 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 p {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
  opacity: 0.9;
}

.note {
  background: var(--white);
  color: var(--primary);
  padding: 1rem;
  border-radius: 8px;
  margin: 2rem auto;
  max-width: 800px;
  text-align: center;
  box-shadow: 0 4px 6px rgba(0,0,0,0.05);
  font-weight: bold;
  border-left: 4px solid var(--secondary);
}

.main-content {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: 2rem;
  margin-bottom: 3rem;
}

.sidebar {
  position: sticky;
  top: 20px;
  align-self: start;
  background: var(--white);
  border-radius: 12px;
  padding: 1.5rem;
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.sidebar h3 {
  color: var(--primary);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--gray);
}

.sidebar ul {
  list-style: none;
}

.sidebar li {
  margin-bottom: 0.8rem;
}

.sidebar a {
  color: var(--dark);
  text-decoration: none;
  transition: color 0.3s ease;
  display: block;
  padding: 0.5rem 0;
  position: relative;
}

.sidebar a:hover {
  color: var(--secondary);
}

.sidebar a::before {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--secondary);
  transition: width 0.3s ease;
}

.sidebar a:hover::before {
  width: 100%;
}

.content {
  background: var(--white);
  border-radius: 12px;
  padding: 2rem;
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

article h2 {
  color: var(--primary);
  margin: 2rem 0 1rem;
  font-size: 1.8rem;
  position: relative;
  padding-bottom: 0.5rem;
}

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

article h3 {
  color: var(--primary-light);
  margin: 1.5rem 0 1rem;
  font-size: 1.4rem;
}

article p {
  margin-bottom: 1.5rem;
  font-size: 1.1rem;
  line-height: 1.7;
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

.image-card {
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 6px 12px rgba(0,0,0,0.1);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  position: relative;
}

.image-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 24px rgba(0,0,0,0.15);
}

.image-card img {
  width: 100%;
  height: auto;
  display: block;
  transition: transform 0.5s ease;
}

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

.image-card::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(180deg, rgba(0,0,0,0) 60%, rgba(0,0,0,0.3) 100%);
}

pre {
  background: #282c34;
  color: #abb2bf;
  padding: 1.5rem;
  border-radius: 8px;
  overflow-x: auto;
  margin: 1.5rem 0;
  font-size: 0.95rem;
  line-height: 1.5;
  box-shadow: inset 0 0 10px rgba(0,0,0,0.3);
}

code {
  font-family: 'Fira Code', monospace;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

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

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

tr:nth-child(even) {
  background-color: var(--gray);
}

tr:hover {
  background-color: rgba(30, 60, 114, 0.05);
}

.footer {
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: var(--white);
  padding: 2rem 0;
  text-align: center;
  margin-top: 3rem;
}

.footer p {
  max-width: 800px;
  margin: 0 auto;
}

@media (max-width: 900px) {
  .main-content {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    position: static;
    margin-bottom: 2rem;
  }
  
  .image-grid {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  }
}

@media (max-width: 600px) {
  .header h1 {
    font-size: 2rem;
  }
  
  .header p {
    font-size: 1rem;
  }
  
  article h2 {
    font-size: 1.5rem;
  }
  
  article h3 {
    font-size: 1.2rem;
  }
  
  .image-grid {
    grid-template-columns: 1fr;
  }
}

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

.content {
  animation: fadeIn 0.8s ease-out;
}

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

.header h1 {
  animation: pulse 2s infinite;
}