/* ============ LAYOUT ============ */
  main {
    flex: 1;
    max-width: 1400px;
    margin: 0 auto;
    padding: 40px 48px 100px;
    width: 100%;
    display: grid;
    grid-template-columns: 320px 1fr;
    gap: 80px;
    align-items: start;
  }

  /* ============ SIDEBAR ============ */
  .sidebar {
    position: sticky;
    top: 32px;
    max-height: calc(100vh - 64px);
    overflow-y: auto;
    padding-right: 8px;
  }
  .sidebar::-webkit-scrollbar { width: 4px; }
  .sidebar::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.1); border-radius: 2px; }

  .sidebar-nav {
    list-style: none;
    display: flex;
    flex-direction: column;
  }
  .sidebar-nav li {
    border-bottom: 1px solid rgba(255,255,255,0.06);
    transition: border-color 0.2s;
  }
  .sidebar-nav li:hover,
  .sidebar-nav li.active {
    border-bottom-color: #fff;
  }
  .sidebar-nav a {
    display: block;
    padding: 20px 4px;
    font-size: 16px;
    font-weight: 400;
    color: var(--text-primary);
    letter-spacing: -0.01em;
    transition: color 0.2s, padding 0.2s;
    cursor: pointer;
  }
  .sidebar-nav a:hover {
    padding-left: 10px;
  }
  .sidebar-nav a.active {
    font-weight: 500;
  }

  /* ============ CONTENT ============ */
  .content { max-width: 820px; }

  .content h1 {
    font-size: 72px;
    font-weight: 600;
    letter-spacing: -0.03em;
    line-height: 1.05;
    margin-bottom: 32px;
  }
  .last-updated {
    color: var(--text-secondary);
    font-size: 17px;
    margin-bottom: 36px;
  }
  .intro {
    font-size: 19px;
    line-height: 1.6;
    color: #E4E8F0;
    margin-bottom: 72px;
    font-weight: 300;
  }

  .content section {
    margin-bottom: 64px;
    scroll-margin-top: 32px;
  }
  .content h2 {
    font-size: 34px;
    font-weight: 600;
    letter-spacing: -0.02em;
    margin-bottom: 28px;
    line-height: 1.2;
  }
  .content h3 {
    font-size: 20px;
    font-weight: 600;
    margin: 28px 0 14px;
    color: #fff;
  }
  .content p {
    font-size: 17px;
    line-height: 1.65;
    color: #D5DAE3;
    margin-bottom: 18px;
    font-weight: 300;
  }
  .content ul {
    margin: 0 0 18px 22px;
    padding: 0;
  }
  .content li {
    font-size: 17px;
    line-height: 1.65;
    color: #D5DAE3;
    margin-bottom: 10px;
    font-weight: 300;
  }
  .content strong { color: #fff; font-weight: 600; }
  .content a.inline { color: var(--accent-blue); text-decoration: underline; text-underline-offset: 3px; }

  /* ============ RESPONSIVE ============ */
  @media (max-width: 960px) {
    main {
      grid-template-columns: 1fr;
      gap: 40px;
      padding: 24px 24px 60px;
    }
    .sidebar {
      position: static;
      max-height: none;
      border: 1px solid var(--card-border);
      border-radius: 16px;
      padding: 8px 20px;
      background: rgba(15, 20, 35, 0.4);
    }
    .content h1 { font-size: 48px; }
    .content h2 { font-size: 26px; }
    nav { padding: 20px 24px; flex-wrap: wrap; }
    .nav-links { display: none; }
  }
  @media (max-width: 600px) {
    .content h1 { font-size: 38px; }
    .intro { font-size: 17px; }
    .nav-cta .btn-ghost { display: none; }
  }