:root {
  --primary: #2E4053;
  --secondary: #B0C4DE;
  --accent: #FFA726;
  --text: #333333;
  --light: #FFFFFF;
  --dark: #1A1A1A;
  --radius: 12px;
  --shadow: 0 8px 24px rgba(0,0,0,0.1);
}

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

body {
  font-family: 'Helvetica Neue', Arial, sans-serif;
  line-height: 1.6;
  color: var(--text);
  background: linear-gradient(135deg, #f5f7fa 0%, #e4e8eb 100%);
  padding: 0;
  margin: 0;
  min-height: 100%;
}

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

.header {
  text-align: center;
  margin-bottom: 3rem;
  position: relative;
}

.header::after {
  content: "";
  display: block;
  width: 120px;
  height: 4px;
  background: linear-gradient(to right, var(--accent), var(--primary));
  margin: 1.5rem auto;
  border-radius: 2px;
}

h1, h2, h3, h4 {
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: 1rem;
  color: var(--primary);
}

h1 {
  font-size: 2.5rem;
  background: linear-gradient(to right, var(--primary), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  display: inline-block;
}

h2 {
  font-size: 2rem;
  margin-top: 3rem;
  position: relative;
  padding-bottom: 0.5rem;
}

h2::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: var(--accent);
  border-radius: 3px;
}

h3 {
  font-size: 1.5rem;
  margin-top: 2rem;
  color: var(--primary);
}

p {
  margin-bottom: 1.5rem;
  font-size: 1.1rem;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: all 0.3s ease;
}

a:hover {
  color: var(--primary);
  text-decoration: underline;
}

.card {
  background: var(--light);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 2rem;
  margin-bottom: 2rem;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  border: 1px solid rgba(0,0,0,0.05);
}

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

.img-container {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin: 2rem 0;
}

.img-box {
  flex: 1 1 300px;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform 0.3s ease;
}

.img-box:hover {
  transform: scale(1.03);
}

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

.img-box:hover img {
  transform: scale(1.1);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  background: var(--light);
  box-shadow: var(--shadow);
  border-radius: var(--radius);
  overflow: hidden;
}

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

th {
  background: var(--primary);
  color: var(--light);
  font-weight: 600;
}

tr:nth-child(even) {
  background: rgba(0,0,0,0.02);
}

pre {
  background: var(--dark);
  color: #f8f8f2;
  padding: 1.5rem;
  border-radius: var(--radius);
  overflow-x: auto;
  margin: 2rem 0;
  box-shadow: var(--shadow);
  font-family: 'Courier New', monospace;
  font-size: 0.95rem;
  line-height: 1.5;
  position: relative;
}

pre::before {
  content: "CSS";
  position: absolute;
  top: 0;
  right: 0;
  background: var(--accent);
  color: var(--light);
  padding: 0.25rem 0.75rem;
  font-size: 0.8rem;
  border-bottom-left-radius: var(--radius);
}

code {
  font-family: 'Courier New', monospace;
  background: rgba(0,0,0,0.05);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-size: 0.9rem;
}

.note {
  background: rgba(255,167,38,0.1);
  border-left: 4px solid var(--accent);
  padding: 1rem;
  margin: 2rem 0;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.note p {
  margin: 0;
}

.footer {
  text-align: center;
  margin-top: 4rem;
  padding: 2rem 0;
  border-top: 1px solid var(--secondary);
  color: var(--primary);
}

@media (max-width: 768px) {
  .container {
    padding: 1rem;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.75rem;
  }
  
  h3 {
    font-size: 1.25rem;
  }
  
  .img-box {
    flex: 1 1 100%;
  }
}

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

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

.delay-1 { animation-delay: 0.2s; }
.delay-2 { animation-delay: 0.4s; }
.delay-3 { animation-delay: 0.6s; }

/* Navigation */
.nav-links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1rem;
  margin: 2rem 0;
}

.nav-link {
  padding: 0.75rem 1.5rem;
  background: var(--primary);
  color: var(--light);
  border-radius: 50px;
  transition: all 0.3s ease;
  font-weight: 500;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.nav-link:hover {
  background: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(0,0,0,0.15);
  text-decoration: none;
}

.reference {
  background: var(--light);
  padding: 1rem;
  border-radius: var(--radius);
  margin: 2rem 0;
  text-align: center;
  font-weight: 500;
  box-shadow: var(--shadow);
  border: 1px solid rgba(0,0,0,0.05);
}