/* --- DESIGN SYSTEM PROTOKIN (Intégré) --- */
    :root {
      --theme-color: #2c3e50;
      --base-background: #ffffff;
      --sidebar-background: #fdfdfd;
      --text-color: #1a1a1a;
      --text-muted: #666666;
      --accent-color: #8e44ad;
      --border-color: #eeeeee;
      --font-serif: 'Noto Serif', 'Georgia', serif;
      --font-sans: 'Inter', system-ui, sans-serif;
    }

    body {
      font-family: var(--font-serif);
      color: var(--text-color);
      background-color: var(--base-background);
      line-height: 1.8;
    }

    /* Ajustement de la section de contenu */
    .markdown-section {
      max-width: 800px;
      margin: 0 auto;
      padding: 3rem 45px 5rem;
      font-size: 1.15rem;
    }

    /* Typographie NRF */
    h1, h2, h3 {
      font-family: var(--font-serif);
      color: var(--theme-color);
      margin-top: 2.5em;
      font-weight: 700;
    }

    h1 { font-size: 2.8rem; border-bottom: 1px solid var(--border-color); padding-bottom: 1rem; }
    h2 { font-size: 1.9rem; border-left: 5px solid var(--theme-color); padding-left: 1.2rem; margin-top: 3rem; }
    h3 { font-size: 1.5rem; font-style: italic; color: #444; }

    p { margin-bottom: 1.8rem; text-align: justify; }

    /* Blocs d'équations et technique */
    .math.display {
      background: #f9f9f9;
      padding: 2rem;
      border-radius: 4px;
      margin: 2.5rem 0;
      border: 1px solid var(--border-color);
      box-shadow: inset 0 1px 3px rgba(0,0,0,0.02);
    }

    blockquote {
      border-left: 4px solid var(--accent-color);
      color: var(--text-muted);
      font-style: italic;
      margin: 2.5rem 0;
      padding: 1rem 2rem;
      background-color: #fcfcfc;
    }

    code {
      font-family: 'Fira Code', monospace;
      background-color: #f4f4f4;
      padding: 0.2rem 0.5rem;
      border-radius: 3px;
      font-size: 0.9em;
    }

    /* Sidebar (Le Registre) */
    .sidebar {
      background-color: var(--sidebar-background);
      border-right: 1px solid var(--border-color);
      font-family: var(--font-sans);
    }

    .sidebar-nav li a {
      font-size: 0.95rem;
      color: var(--text-muted);
    }

    .sidebar-nav li.active > a {
      color: var(--theme-color);
      font-weight: 700;
      border-right: 3px solid var(--theme-color);
    }

    /* Interface de recherche */
    .search input {
      border-radius: 20px !important;
      background: #f0f0f0 !important;
      padding: 10px 15px !important;
    }

    /* Mobile */
    @media screen and (max-width: 768px) {
      .markdown-section {
        padding: 2rem 25px;
        text-align: left;
      }
      h1 { font-size: 2.2rem; }
    }

.katex-display {
  background: #f8f9fa;
  padding: 15px;
  border-radius: 8px;
  overflow-x: auto;
}