:root {
  --primary-color: #1E1E1E;
  --accent-blue: #4A90E2;
  --accent-red: #E74C3C;
  --text-color: #FFFFFF;
  --text-light: #B0B0B0;
  --card-bg: linear-gradient(135deg, #2C2C2C, #1E1E1E);
  --transition: all 0.3s ease;
}

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

body {
  background-color: var(--primary-color);
  color: var(--text-color);
  font-family: 'Roboto', 'Helvetica Neue', Arial, sans-serif;
  line-height: 1.6;
  overflow-x: hidden;
}

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

.header {
  text-align: center;
  padding: 40px 0;
  background: linear-gradient(to right, #1E1E1E, #2C2C2C, #1E1E1E);
  margin-bottom: 40px;
  position: relative;
  overflow: hidden;
}

.header::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 50% 50%, rgba(74, 144, 226, 0.1), transparent 70%);
  pointer-events: none;
}

.header h1 {
  font-size: 2.5rem;
  margin-bottom: 15px;
  background: linear-gradient(to right, #4A90E2, #E74C3C);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  position: relative;
  z-index: 1;
}

.header p {
  color: var(--text-light);
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.reference-note {
  background-color: rgba(74, 144, 226, 0.2);
  padding: 15px;
  border-radius: 8px;
  margin: 30px auto;
  max-width: 800px;
  text-align: center;
  border: 1px solid rgba(74, 144, 226, 0.5);
  box-shadow: 0 0 20px rgba(74, 144, 226, 0.1);
}

.reference-note p {
  color: var(--accent-blue);
  font-weight: bold;
}

.content-section {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: 30px;
  margin-bottom: 60px;
}

@media (max-width: 992px) {
  .content-section {
    grid-template-columns: 1fr;
  }
}

.side-nav {
  position: sticky;
  top: 20px;
  align-self: start;
  background: var(--card-bg);
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
  border: 1px solid #333;
}

.side-nav h3 {
  color: var(--accent-blue);
  margin-bottom: 15px;
  padding-bottom: 10px;
  border-bottom: 1px solid #333;
}

.side-nav ul {
  list-style: none;
}

.side-nav li {
  margin-bottom: 10px;
}

.side-nav a {
  color: var(--text-light);
  text-decoration: none;
  display: block;
  padding: 8px 12px;
  border-radius: 6px;
  transition: var(--transition);
}

.side-nav a:hover {
  background-color: rgba(74, 144, 226, 0.1);
  color: var(--accent-blue);
}

.main-content {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 30px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
  border: 1px solid #333;
}

article h2 {
  color: var(--accent-blue);
  margin: 30px 0 20px;
  font-size: 1.8rem;
  position: relative;
  padding-bottom: 10px;
}

article h2::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: linear-gradient(to right, var(--accent-blue), var(--accent-red));
}

article h3 {
  color: var(--text-color);
  margin: 25px 0 15px;
  font-size: 1.4rem;
}

article p {
  margin-bottom: 20px;
  color: var(--text-light);
  line-height: 1.7;
}

article strong {
  color: var(--accent-blue);
}

article span {
  color: var(--accent-red);
  font-weight: bold;
}

pre {
  background: #2C2C2C;
  border-radius: 8px;
  padding: 20px;
  margin: 20px 0;
  overflow: auto;
  border: 1px solid #333;
  box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.5);
}

code {
  font-family: 'Courier New', monospace;
  color: #E74C3C;
}

.language-css {
  color: #B0B0B0;
}

.language-css .token.property {
  color: #4A90E2;
}

.language-css .token.selector {
  color: #E74C3C;
}

.language-css .token.punctuation {
  color: #B0B0B0;
}

.language-css .token.function {
  color: #4A90E2;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  background: #2C2C2C;
  border-radius: 8px;
  overflow: hidden;
}

th, td {
  padding: 12px 15px;
  text-align: left;
  border: 1px solid #333;
}

th {
  background-color: var(--accent-blue);
  color: var(--text-color);
}

td {
  color: var(--text-light);
}

tr:nth-child(even) {
  background-color: rgba(74, 144, 226, 0.05);
}

tr:hover {
  background-color: rgba(74, 144, 226, 0.1);
}

.image-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin: 30px 0;
}

.gallery-item {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
  transition: var(--transition);
}

.gallery-item:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.4);
}

.gallery-item img {
  width: 100%;
  height: 300px;
  object-fit: cover;
  display: block;
  transition: var(--transition);
}

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

.gallery-caption {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: linear-gradient(to top, rgba(30, 30, 30, 0.9), transparent);
  padding: 20px;
  color: white;
}

.accordion {
  margin: 20px 0;
}

.accordion-item {
  margin-bottom: 10px;
  border-radius: 8px;
  overflow: hidden;
  background: #2C2C2C;
  border: 1px solid #333;
}

.accordion-header {
  padding: 15px 20px;
  background: rgba(74, 144, 226, 0.1);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: var(--transition);
}

.accordion-header:hover {
  background: rgba(74, 144, 226, 0.2);
}

.accordion-content {
  padding: 0 20px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}

.accordion-content-inner {
  padding: 20px 0;
}

.accordion-item.active .accordion-content {
  max-height: 1000px;
}

.accordion-icon {
  transition: transform 0.3s ease;
}

.accordion-item.active .accordion-icon {
  transform: rotate(180deg);
}

.footer {
  text-align: center;
  padding: 30px 0;
  margin-top: 60px;
  border-top: 1px solid #333;
  color: var(--text-light);
}

@media (max-width: 768px) {
  .header h1 {
    font-size: 2rem;
  }
  
  .content-section {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  
  .side-nav {
    position: static;
  }
  
  .image-gallery {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  }
}

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

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