:root {
    --primary: linear-gradient(135deg, #1e3c72 0%, #2a5298 70%);
    --secondary: #f0f2f5;
    --accent: #00c6ff;
    --text: #333;
    --light: #fff;
    --dark: #1a1a2e;
    --radius: 12px;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  }

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

  body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.8;
    color: var(--text);
    background: var(--secondary);
    overflow-x: hidden;
  }

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

  header {
    background: var(--primary);
    color: var(--light);
    padding: 2rem 0;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow);
  }

  header::before {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
    transform: rotate(30deg);
    z-index: 0;
  }

  .header-content {
    position: relative;
    z-index: 1;
    text-align: center;
  }

  .header-content h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    text-shadow: 0 2px 10px rgba(0,0,0,0.3);
  }

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

  .notice {
    background: var(--light);
    color: var(--dark);
    padding: 1rem;
    border-radius: var(--radius);
    margin: 2rem auto;
    max-width: 800px;
    text-align: center;
    box-shadow: var(--shadow);
    font-weight: bold;
  }

  .nav-container {
    background: rgba(26, 26, 46, 0.9);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 20px rgba(0,0,0,0.2);
  }

  nav {
    display: flex;
    justify-content: center;
    padding: 1rem 0;
  }

  nav a {
    color: var(--light);
    text-decoration: none;
    padding: 0.5rem 1.5rem;
    margin: 0 0.5rem;
    border-radius: 30px;
    transition: var(--transition);
    font-weight: 500;
  }

  nav a:hover {
    background: rgba(255,255,255,0.2);
    transform: translateY(-2px);
  }

  main {
    padding: 3rem 0;
  }

  article {
    background: var(--light);
    border-radius: var(--radius);
    padding: 2.5rem;
    box-shadow: var(--shadow);
    margin-bottom: 3rem;
  }

  article h2 {
    font-size: 2rem;
    color: var(--dark);
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 0.5rem;
  }

  article h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 80px;
    height: 4px;
    background: var(--accent);
    border-radius: 2px;
  }

  article h3 {
    font-size: 1.5rem;
    color: var(--dark);
    margin: 2rem 0 1rem;
    position: relative;
    padding-left: 1rem;
  }

  article h3::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    height: 60%;
    width: 4px;
    background: var(--accent);
    border-radius: 2px;
  }

  article p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    line-height: 1.8;
  }

  pre {
    background: #282c34;
    border-radius: var(--radius);
    padding: 1.5rem;
    margin: 2rem 0;
    overflow: auto;
    box-shadow: var(--shadow);
    position: relative;
  }

  pre::before {
    content: "CSS";
    position: absolute;
    top: 0;
    left: 0;
    background: var(--accent);
    color: var(--light);
    padding: 0.2rem 1rem;
    border-radius: var(--radius) 0 var(--radius) 0;
    font-size: 0.9rem;
    font-weight: bold;
  }

  code {
    font-family: 'Fira Code', monospace;
    color: #abb2bf;
    font-size: 0.95rem;
  }

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

  .gallery img {
    width: 100%;
    height: auto;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
    aspect-ratio: 1/1;
    object-fit: cover;
  }

  .gallery img:hover {
    transform: translateY(-5px) scale(1.02);
    box-shadow: 0 15px 30px rgba(0,0,0,0.2);
  }

  .split-layout {
    display: flex;
    gap: 2rem;
    margin: 3rem 0;
  }

  .split-layout > div {
    flex: 1;
    background: var(--light);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow);
  }

  .chart-container {
    height: 300px;
    background: var(--light);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin: 2rem 0;
    box-shadow: var(--shadow);
    display: flex;
    align-items: flex-end;
    justify-content: space-around;
  }

  .chart-bar {
    width: 40px;
    background: var(--accent);
    transition: var(--transition);
    border-radius: 4px 4px 0 0;
    position: relative;
  }

  .chart-bar:hover {
    transform: scaleY(1.1);
    background: #ff9900;
  }

  .chart-bar::after {
    content: attr(data-value);
    position: absolute;
    top: -25px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--dark);
    color: var(--light);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-size: 0.8rem;
    opacity: 0;
    transition: var(--transition);
  }

  .chart-bar:hover::after {
    opacity: 1;
    top: -30px;
  }

  .collapsible {
    background: var(--primary);
    color: var(--light);
    cursor: pointer;
    padding: 1.2rem;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 1.1rem;
    border-radius: var(--radius);
    margin: 1rem 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow);
    transition: var(--transition);
  }

  .collapsible:hover {
    background: #2a5298;
  }

  .collapsible::after {
    content: "+";
    font-size: 1.5rem;
    transition: var(--transition);
  }

  .collapsible.active::after {
    content: "-";
  }

  .content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    background: var(--light);
    border-radius: 0 0 var(--radius) var(--radius);
    box-shadow: var(--shadow);
  }

  .content-inner {
    padding: 2rem;
  }

  footer {
    background: var(--dark);
    color: var(--light);
    padding: 3rem 0;
    text-align: center;
  }

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

  .footer-links {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    margin: 1.5rem 0;
  }

  .footer-links a {
    color: var(--light);
    text-decoration: none;
    margin: 0 1rem;
    opacity: 0.8;
    transition: var(--transition);
  }

  .footer-links a:hover {
    opacity: 1;
    color: var(--accent);
  }

  @media (max-width: 768px) {
    .split-layout {
      flex-direction: column;
    }
    
    nav {
      flex-wrap: wrap;
    }
    
    nav a {
      margin: 0.3rem;
      padding: 0.5rem 1rem;
    }
    
    article {
      padding: 1.5rem;
    }
    
    .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;
  }

  @keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
  }

  .pulse {
    animation: pulse 2s ease-in-out infinite;
  }