:root {
         --primary-color: #3498db;
         --secondary-color: #2c3e50;
         --accent-color: #e74c3c;
         --success-color: #2ecc71;
         --warning-color: #f39c12;
         --bg-color: #f8fafc;
         --card-bg: #ffffff;
         --text-color: #2d3748;
         --text-muted: #718096;
         --border-color: #e2e8f0;
         --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
         --presentation-yellow-bg: #fff8e1;
         --presentation-blue-text: #1565c0;
      }
      [data-theme="dark"] {
         --bg-color: #1a202c;
         --card-bg: #2d3748;
         --text-color: #f7fafc;
         --text-muted: #a0aec0;
         --border-color: #4a5568;
         --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
      }
      * {
         box-sizing: border-box;
      }

      .header-top {
         display: flex;
         align-items: center;
         gap: 15px;
         margin-bottom: 10px;
      }
      .header-bottom {
         display: flex;
         align-items: center;
         gap: 15px;
         flex-wrap: wrap;
      }
      .header h1 {
         margin: 0;
         font-size: 1.1em;
         font-weight: 600;
         color: white;
         flex-grow: 1;
         text-align: left;
      }
      /* Search Box */
      .search-container {
         position: relative;
         flex-grow: 1;
         max-width: 300px;
      }
      .search-box {
         width: 100%;
         padding: 8px 40px 8px 12px;
         border: 2px solid rgba(255,255,255,0.2);
         border-radius: 25px;
         background: rgba(255,255,255,0.1);
         color: white;
         font-size: 14px;
         transition: all 0.3s ease;
      }
      .search-box::placeholder {
         color: rgba(255,255,255,0.7);
      }
      .search-box:focus {
         outline: none;
         border-color: rgba(255,255,255,0.5);
         background: rgba(255,255,255,0.2);
      }
      .search-icon {
         position: absolute;
         right: 12px;
         top: 50%;
         transform: translateY(-50%);
         color: rgba(255,255,255,0.7);
      }
      /* Header Controls */
      .header-controls {
         display: flex;
         align-items: center;
         gap: 10px;
      }
      .control-btn {
         background: rgba(255,255,255,0.1);
         border: 1px solid rgba(255,255,255,0.2);
         color: white;
         padding: 8px 12px;
         border-radius: 6px;
         cursor: pointer;
         transition: all 0.3s ease;
         font-size: 14px;
      }
      .control-btn:hover {
         background: rgba(255,255,255,0.2);
         transform: translateY(-1px);
      }
      /* Botão de tela cheia */
      .fullscreen-btn {
         background: rgba(255,255,255,0.1);
         border: 1px solid rgba(255,255,255,0.2);
         color: white;
         width: 36px;
         height: 36px;
         border-radius: 50%;
         cursor: pointer;
         transition: all 0.3s ease;
         display: flex;
         align-items: center;
         justify-content: center;
         font-size: 16px;
		 right: 230px;
      }
      .fullscreen-btn:hover {
         background: rgba(255,255,255,0.2);
         transform: scale(1.1);
      }
      .theme-toggle {
         background: none;
         border: none;
         color: white;
         font-size: 18px;
         cursor: pointer;
         padding: 8px;
         border-radius: 50%;
         transition: all 0.3s ease;
      }
      .theme-toggle:hover {
         background: rgba(255,255,255,0.1);
         transform: scale(1.1);
      }
      /* Hamburger Menu */
      .hamburger {
         display: flex;
         flex-direction: column;
         justify-content: space-around;
         width: 30px;
         height: 24px;
         cursor: pointer;
         transition: all 0.3s ease;
         padding: 4px;
         border-radius: 4px;
      }
      .hamburger:hover {
         background: rgba(255,255,255,0.1);
      }
      .hamburger span {
         display: block;
         height: 3px;
         width: 100%;
         background-color: white;
         border-radius: 3px;
         transition: all 0.3s ease;
      }
      .hamburger.active {
         transform: rotate(45deg);
      }
      .hamburger.active span:nth-child(1) {
         transform: rotate(90deg) translate(-50%, -50%);
      }
      .hamburger.active span:nth-child(2) {
         opacity: 0;
      }
      .hamburger.active span:nth-child(3) {
         transform: rotate(90deg) translate(50%, 50%);
      }
      /* Botão para mostrar/ocultar header */
      .header-toggle-btn {
         position: fixed;
         top: 10px;
         left: 50%;
         transform: translateX(-50%);
         background: var(--primary-color);
         color: white;
         border: none;
         padding: 8px 16px;
         border-radius: 20px;
         cursor: pointer;
         transition: all 0.3s ease;
         z-index: 1001;
         display: flex;
         align-items: center;
         gap: 8px;
         font-size: 14px;
         box-shadow: var(--shadow);
      }
      .header-toggle-btn:hover {
         background: var(--secondary-color);
         transform: translateX(-50%) translateY(-2px);
      }
      /* Sidebar Menu */
      .sidebar {
         position: fixed;
         top: 120px;
         left: -380px;
         width: 350px;
         height: calc(100vh - 120px);
         background: var(--card-bg);
         color: var(--text-color);
         padding: 20px;
         transition: all 0.3s ease;
         z-index: 999;
         overflow-y: auto;
         box-shadow: var(--shadow);
         border-right: 3px solid var(--primary-color);
      }
      .sidebar.active {
         left: 0;
      }
      .sidebar h3 {
         color: var(--primary-color);
         margin-top: 0;
         margin-bottom: 20px;
         font-size: 1.2em;
         font-weight: 600;
         border-bottom: 2px solid var(--primary-color);
         padding-bottom: 10px;
         display: flex;
         align-items: center;
         gap: 8px;
      }
      .sidebar ul {
         list-style-type: none;
         padding-left: 0;
      }
      .sidebar li {
         margin-bottom: 4px;
      }
      .sidebar a {
         color: var(--text-muted);
         text-decoration: none;
         display: flex;
         align-items: center;
         padding: 12px;
         border-radius: 8px;
         transition: all 0.3s ease;
         gap: 10px;
         font-weight: 500;
      }
      .sidebar a:hover, .sidebar a.active {
         background: linear-gradient(135deg, var(--primary-color), rgba(52, 152, 219, 0.1));
         color: white;
         transform: translateX(8px);
         box-shadow: 0 2px 8px rgba(52, 152, 219, 0.3);
      }
      .sidebar a i {
         width: 20px;
         text-align: center;
      }
      /* Tools Sidebar */
      .tools-sidebar {
         position: fixed;
         top: 120px;
         right: -380px;
         width: 350px;
         height: calc(100vh - 120px);
         background: var(--card-bg);
         color: var(--text-color);
         padding: 20px;
         transition: all 0.3s ease;
         z-index: 20000;
         overflow-y: auto;
         box-shadow: var(--shadow);
         border-left: 3px solid var(--primary-color);
      }
      .tools-sidebar.active {
         right: 0;
      }
      .tools-sidebar h3 {
         color: var(--primary-color);
         margin-top: 0;
         margin-bottom: 20px;
         font-size: 1.2em;
         font-weight: 600;
         border-bottom: 2px solid var(--primary-color);
         padding-bottom: 10px;
         display: flex;
         align-items: center;
         gap: 8px;
      }
      .tools-grid {
         display: grid;
         grid-template-columns: repeat(2, 1fr);
         gap: 15px;
      }
      .tool-item {
         background: var(--bg-color);
         border: 1px solid var(--border-color);
         border-radius: 12px;
         padding: 20px;
         text-align: center;
         cursor: pointer;
         transition: all 0.3s ease;
         display: flex;
         flex-direction: column;
         align-items: center;
         gap: 10px;
      }
      .tool-item:hover {
         border-color: var(--primary-color);
         transform: translateY(-3px);
         box-shadow: var(--shadow);
      }
      .tool-item i {
         font-size: 2em;
         color: var(--primary-color);
      }
      .tool-item h4 {
         margin: 0;
         font-size: 0.9em;
         color: var(--text-color);
      }
      .tool-item p {
         margin: 0;
         font-size: 0.8em;
         color: var(--text-muted);
      }
      /* Submenu Styles */
      .submenu {
         max-height: 0;
         overflow: hidden;
         transition: max-height 0.3s ease;
         padding-left: 20px;
      }
      .submenu.active {
         max-height: 500px;
      }
      .submenu-toggle {
         cursor: pointer;
         display: flex;
         align-items: center;
         justify-content: space-between;
         width: 100%;
      }
      .submenu-icon {
         transition: transform 0.3s ease;
         font-size: 0.8em;
      }
      .submenu-toggle.active .submenu-icon {
         transform: rotate(90deg);
      }
      /* Submenu de segundo nível */
      .submenu-2 {
         max-height: 0;
         overflow: hidden;
         transition: max-height 0.3s ease;
         padding-left: 20px;
      }
      .submenu-2.active {
         max-height: 500px;
      }
      /* Submenu de terceiro nível */
      .submenu-3 {
         max-height: 0;
         overflow: hidden;
         transition: max-height 0.3s ease;
         padding-left: 20px;
      }
      .submenu-3.active {
         max-height: 500px;
      }
      /* Overlay */
      .overlay {
         position: fixed;
         top: 0;
         left: 0;
         right: 0;
         bottom: 0;
         background-color: rgba(0,0,0,0.5);
         z-index: 998;
         opacity: 0;
         visibility: hidden;
         transition: all 0.3s ease;
      }
      .overlay.active {
         opacity: 1;
         visibility: visible;
      }
      .container {
         max-width: 1000px;
         margin: 0 auto;
         background: var(--card-bg);
         padding: 40px;
         border-radius: 16px;
         box-shadow: var(--shadow);
         border: 1px solid var(--border-color);
         position: relative;
         overflow: hidden;
         transition: all 0.3s ease;
      }
      .container::before {
         content: '';
         position: absolute;
         top: 0;
         left: 0;
         right: 0;
         height: 4px;
         background: linear-gradient(90deg, var(--primary-color), var(--success-color));
      }
      /* Modo Foco */
      body.focus-mode .header,
      body.focus-mode .sidebar,
      body.focus-mode .tools-sidebar,
      body.focus-mode .overlay,
      body.focus-mode .scroll-top,
      body.focus-mode .header-toggle-btn {
         display: none !important;
      }
      body.focus-mode {
         padding: 20px !important;
      }
      body.focus-mode .container {
         max-width: 800px;
         margin: 0 auto;
         border-radius: 0;
         box-shadow: none;
         border: none;
      }
      /* Botão sair do modo foco */
      .exit-focus-btn {
         position: fixed;
         top: 20px;
         right: 20px;
         background: var(--primary-color);
         color: white;
         border: none;
         padding: 10px 20px;
         border-radius: 25px;
         cursor: pointer;
         transition: all 0.3s ease;
         display: none;
         z-index: 1001;
         box-shadow: var(--shadow);
      }
      body.focus-mode .exit-focus-btn {
         display: flex;
         align-items: center;
         gap: 8px;
      }
      .exit-focus-btn:hover {
         background: var(--secondary-color);
         transform: translateY(-2px);
      }
      /* Modo Apresentação */
      body.presentation-mode {
         background: #000;
         color: #fff;
         overflow-y: auto;
      }
      body.presentation-mode .header,
      body.presentation-mode .sidebar,
      body.presentation-mode .tools-sidebar,
      body.presentation-mode .overlay,
      body.presentation-mode .scroll-top,
      body.presentation-mode .header-toggle-btn {
         display: none !important;
      }
      body.presentation-mode .container {
         max-width: 100%;
         margin: 0;
         padding: 0;
         border-radius: 0;
         box-shadow: none;
         border: none;
         background: #000;
      }
      body.presentation-mode .section {
         display: none;
         min-height: 100vh;
         padding: 60px;
         position: relative;
         background: #000;
      }
      body.presentation-mode .section.active {
         display: block;
      }
      body.presentation-mode .section h2 {
         font-size: 3em;
         margin-bottom: 40px;
         text-align: center;
      }
      body.presentation-mode .section h3 {
         font-size: 2em;
         margin-bottom: 30px;
      }
      body.presentation-mode .section p {
         font-size: 1.5em;
         margin-bottom: 20px;
      }
      body.presentation-mode .section .formula {
         font-size: 1.8em;
         padding: 30px;
         margin: 30px 0;
      }
      body.presentation-mode .section .comparison {
         grid-template-columns: 1fr 1fr;
         gap: 40px;
      }
      body.presentation-mode .section .comparison-item {
         padding: 30px;
         font-size: 1.2em;
      }
      /* ===== ALTERAÇÃO APLICADA ===== */
      /* Cor azul para todo o texto no modo apresentação */
      body.presentation-mode .section {
         color: var(--presentation-blue-text) !important;
      }
      body.presentation-mode .section h2,
      body.presentation-mode .section h3,
      body.presentation-mode .section h4,
      body.presentation-mode .section h5,
      body.presentation-mode .section p,
      body.presentation-mode .section li,
      body.presentation-mode .section .formula,
      body.presentation-mode .section .note,
      body.presentation-mode .section .note h4,
      body.presentation-mode .section .note p,
      body.presentation-mode .section .comparison-item,
      body.presentation-mode .section .comparison-item h4,
      body.presentation-mode .section .comparison-item p {
         color: var(--presentation-blue-text) !important;
      }
      /* Mantém os fundos amarelos para elementos específicos */
      body.presentation-mode .note {
         background: var(--presentation-yellow-bg);
      }
      body.presentation-mode .formula {
         background: var(--presentation-yellow-bg);
      }
      /* ===== FIM DA ALTERAÇÃO ===== */
      .presentation-controls {
         position: fixed;
         top: 20px;
         left: 0;
         right: 0;
         display: none;
         justify-content: space-between;
         align-items: center;
         padding: 0 40px;
         z-index: 1000;
      }
      body.presentation-mode .presentation-controls {
         display: flex;
      }
      .presentation-controls button {
         background: rgba(255,255,255,0.2);
         border: 1px solid rgba(255,255,255,0.3);
         color: white;
         padding: 12px 20px;
         border-radius: 25px;
         cursor: pointer;
         transition: all 0.3s ease;
         font-size: 16px;
         display: flex;
         align-items: center;
         gap: 8px;
      }
      .presentation-controls button:hover {
         background: rgba(255,255,255,0.3);
         transform: scale(1.05);
      }
      .slide-counter {
         color: white;
         font-size: 18px;
         font-weight: 600;
         background: rgba(255,255,255,0.1);
         padding: 10px 20px;
         border-radius: 25px;
         border: 1px solid rgba(255,255,255,0.3);
      }
      /* Barra de progresso da apresentação */
      .presentation-progress {
         position: fixed;
         bottom: 80px;
         left: 50%;
         transform: translateX(-50%);
         width: 300px;
         height: 6px;
         background: rgba(255, 255, 255, 0.2);
         border-radius: 3px;
         overflow: hidden;
         z-index: 1001;
         display: none;
      }
      body.presentation-mode .presentation-progress {
         display: block;
      }
      .presentation-progress-bar {
         height: 100%;
         background: linear-gradient(90deg, var(--primary-color), var(--success-color));
         width: 0%;
         transition: width 0.1s ease;
      }
      /* Controle de velocidade */
      .speed-control {
         position: fixed;
         bottom: 100px;
         right: 20px;
         background: var(--card-bg);
         padding: 15px;
         border-radius: 12px;
         box-shadow: var(--shadow);
         z-index: 20000;
         display: none;
         flex-direction: column;
         gap: 10px;
         min-width: 200px;
      }
      .speed-control.active {
         display: flex;
      }
      .speed-control h4 {
         margin: 0;
         color: var(--primary-color);
         font-size: 0.9em;
         font-weight: 600;
      }
      .speed-slider {
         width: 100%;
         margin: 10px 0;
      }
      .speed-value {
         text-align: center;
         font-size: 0.9em;
         color: var(--text-muted);
      }
      /* Marcadores */
      .bookmark-btn {
         background: none;
         border: none;
         color: var(--warning-color);
         cursor: pointer;
         font-size: 1.2em;
         transition: all 0.3s ease;
         margin-left: 10px;
      }
      .bookmark-btn:hover {
         transform: scale(1.2);
      }
      .bookmark-list {
         position: fixed;
         bottom: 20px;
         left: 20px;
         background: var(--card-bg);
         padding: 15px;
         border-radius: 12px;
         box-shadow: var(--shadow);
         z-index: 20000;
         display: none;
         flex-direction: column;
         gap: 10px;
         min-width: 250px;
         max-height: 300px;
         overflow-y: auto;
      }
      .bookmark-list.active {
         display: flex;
      }
      .bookmark-list h4 {
         margin: 0;
         color: var(--primary-color);
         font-size: 0.9em;
         font-weight: 600;
      }
      .bookmark-item {
         padding: 8px;
         border-radius: 6px;
         cursor: pointer;
         transition: all 0.3s ease;
         font-size: 0.9em;
         display: flex;
         justify-content: space-between;
         align-items: center;
      }
      .bookmark-item:hover {
         background: var(--bg-color);
      }
      .bookmark-item button {
         background: none;
         border: none;
         color: var(--accent-color);
         cursor: pointer;
         font-size: 0.9em;
         padding: 2px 6px;
      }
      /* Estatísticas de Leitura */
      .reading-stats {
         position: fixed;
         top: 80px;
         right: 20px;
         background: var(--card-bg);
         padding: 15px;
         border-radius: 12px;
         box-shadow: var(--shadow);
         z-index: 20000;
         display: none;
         flex-direction: column;
         gap: 10px;
         min-width: 200px;
      }
      .reading-stats.active {
         display: flex;
      }
      .reading-stats h4 {
         margin: 0;
         color: var(--primary-color);
         font-size: 0.9em;
         font-weight: 600;
      }
      .stat-item {
         display: flex;
         justify-content: space-between;
         font-size: 0.9em;
      }
      .stat-label {
         color: var(--text-muted);
      }
      .stat-value {
         font-weight: 600;
         color: var(--primary-color);
      }
      /* Compartilhamento */
      .share-menu {
         position: fixed;
         top: 50%;
         left: 50%;
         transform: translate(-50%, -50%);
         background: var(--card-bg);
         padding: 20px;
         border-radius: 12px;
         box-shadow: var(--shadow);
         z-index: 10000;
         display: none;
         flex-direction: column;
         gap: 15px;
         min-width: 300px;
      }
      .share-menu.active {
         display: flex;
      }
      .share-menu h3 {
         margin: 0;
         color: var(--primary-color);
         font-size: 1.2em;
         font-weight: 600;
      }
      .share-options {
         display: flex;
         gap: 10px;
         flex-wrap: wrap;
      }
      .share-btn {
         background: var(--primary-color);
         color: white;
         border: none;
         padding: 10px 15px;
         border-radius: 8px;
         cursor: pointer;
         transition: all 0.3s ease;
         display: flex;
         align-items: center;
         gap: 8px;
         font-size: 0.9em;
      }
      .share-btn:hover {
         background: var(--secondary-color);
         transform: translateY(-2px);
      }
      .share-url {
         width: 100%;
         padding: 8px;
         border: 1px solid var(--border-color);
         border-radius: 6px;
         font-size: 0.9em;
      }
      h2 {
         color: var(--primary-color);
         padding: 15px 20px;
         margin-top: 40px;
         margin-bottom: 25px;
         font-weight: 600;
         font-size: 1.8em;
         display: flex;
         align-items: center;
         gap: 12px;
         background: linear-gradient(135deg, var(--primary-color), rgba(52, 152, 219, 0.1));
         border-radius: 8px;
         border-left: 4px solid var(--primary-color);
         animation: slideInLeft 0.6s ease-out;
         color: white;
      }
      h2 i {
         color: white;
      }
      h3 {
         color: var(--secondary-color);
         margin-top: 5px;
         margin-bottom: 20px;
         font-weight: 600;
         font-size: 1.4em;
         display: flex;
         align-items: center;
         gap: 10px;
         padding: 10px 0;
         border-bottom: 2px solid var(--border-color);
      }
      h3 i {
         color: var(--primary-color);
         font-size: 0.9em;
      }
      h4 {
         color: var(--text-color);
         margin-top: 25px;
         margin-bottom: 15px;
         font-weight: 600;
         font-size: 1.2em;
         display: flex;
         align-items: center;
         gap: 8px;
         padding: 8px 0;
         border-bottom: 1px solid var(--border-color);
      }
      h4 i {
         color: var(--primary-color);
         font-size: 0.8em;
      }
      h5 {
         color: var(--text-color);
         margin-top: 20px;
         margin-bottom: 10px;
         font-weight: 600;
         font-size: 1.1em;
         display: flex;
         align-items: center;
         gap: 8px;
         padding: 6px 0;
         border-bottom: 1px dashed var(--border-color);
      }
      h5 i {
         color: var(--primary-color);
         font-size: 0.8em;
      }
      p {
         margin-bottom: 15px;
         text-align: justify;
      }
      .formula {
         background: linear-gradient(135deg, #f0f8ff, #e8f4fd);
         padding: 20px;
         border-radius: 12px;
         margin: 20px 0;
         font-style: italic;
         text-align: center;
         border: 2px solid var(--primary-color);
         box-shadow: 0 4px 12px rgba(52, 152, 219, 0.1);
         font-size: 1.1em;
         font-weight: 500;
         position: relative;
         overflow: hidden;
      }
      .formula::before {
         content: '∑';
         position: absolute;
         top: -10px;
         left: 15px;
         font-size: 3em;
         color: rgba(52, 152, 219, 0.1);
         font-weight: bold;
      }
      figure {
         margin: 20px 0;
         text-align: center;
      }
      figcaption {
         font-style: italic;
         margin-top: 10px;
         color: var(--text-muted);
      }
      .image-placeholder {
         background: linear-gradient(135deg, #f8f9fa, #e9ecef);
         border: 2px dashed var(--border-color);
         height: 250px;
         display: flex;
         align-items: center;
         justify-content: center;
         margin: 15px 0;
         color: var(--text-muted);
         border-radius: 12px;
         transition: all 0.3s ease;
         position: relative;
         overflow: hidden;
         font-weight: 500;
      }
      .image-placeholder:hover {
         border-color: var(--primary-color);
         background: linear-gradient(135deg, rgba(52, 152, 219, 0.1), rgba(52, 152, 219, 0.05));
         transform: scale(1.02);
      }
      .image-placeholder::before {
         content: '🖼';
         font-size: 3em;
         position: absolute;
         top: 50%;
         left: 50%;
         transform: translate(-50%, -70%);
         opacity: 0.3;
      }
      .term {
         font-weight: 600;
         color: var(--accent-color);
         background: rgba(231, 76, 60, 0.1);
         padding: 2px 6px;
         border-radius: 4px;
         cursor: help;
         transition: all 0.3s ease;
         position: relative;
      }
      .term:hover {
         background: var(--accent-color);
         color: white;
         transform: scale(1.05);
      }
      .section {
	  margin-top: -70px;
         margin-bottom: 50px;
         padding: 5px;
         border-radius: 12px;
         background: var(--card-bg);
         border: 1px solid var(--border-color);
         transition: all 0.3s ease;
         opacity: 0;
         transform: translateY(20px);
         animation: fadeInUp 0.6s ease-out forwards;
      }
      .section:hover {
         box-shadow: var(--shadow);
         transform: translateY(-2px);
      }
      .section:nth-child(even) {
         animation-delay: 0.1s;
      }
      .section:nth-child(odd) {
         animation-delay: 0.2s;
      }
      .subsection {
         margin-bottom: 30px;
         padding: 15px;
         border-radius: 10px;
         background: var(--bg-color);
         border: 1px solid var(--border-color);
         transition: all 0.3s ease;
      }
      .subsection:hover {
         box-shadow: var(--shadow);
         transform: translateY(-2px);
      }
      .subsubsection {
         margin-bottom: 25px;
         padding: 12px;
         border-radius: 8px;
         background: var(--bg-color);
         border-left: 3px solid var(--primary-color);
         transition: all 0.3s ease;
      }
      .subsubsection:hover {
         box-shadow: var(--shadow);
         transform: translateX(5px);
      }
      ul {
         padding-left: 20px;
      }
      li {
         margin-bottom: 10px;
		 color: #3f51b5;
      }
      .bibliography {
         margin-top: 40px;
      }
      .bibliography h2 {
         background: linear-gradient(135deg, var(--success-color), rgba(46, 204, 113, 0.1));
         color: white;
         border-left-color: var(--success-color);
      }
      .bibliography-item {
         margin-bottom: 10px;
         padding-left: 20px;
         text-indent: -20px;
      }
      .note {
         background: linear-gradient(135deg, #fff8e1, #fef7cd);
         padding: 20px;
         border-radius: 12px;
         margin: 20px 0;
         border-left: 5px solid var(--warning-color);
         box-shadow: 0 4px 12px rgba(243, 156, 18, 0.1);
         position: relative;
         overflow: hidden;
      }
      .note::before {
         content: '💡';
         position: absolute;
         top: 15px;
         right: 15px;
         font-size: 1.5em;
         opacity: 0.3;
      }
      .note h4 {
         margin-top: 0;
         color: var(--warning-color);
         font-weight: 600;
         display: flex;
         align-items: center;
         gap: 8px;
      }
      .comparison {
         display: grid;
         grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
         gap: 20px;
         margin: 30px 0;
      }
      .comparison-item {
         padding: 20px;
         background: var(--card-bg);
         border-radius: 12px;
         border: 2px solid var(--border-color);
         transition: all 0.3s ease;
         position: relative;
         overflow: hidden;
      }
      .comparison-item::before {
         content: '';
         position: absolute;
         top: 0;
         left: 0;
         right: 0;
         height: 4px;
         background: linear-gradient(90deg, var(--primary-color), var(--success-color));
      }
      .comparison-item:hover {
         border-color: var(--primary-color);
         box-shadow: var(--shadow);
         transform: translateY(-5px);
      }
      .comparison-item h4 {
         margin-top: 0;
         color: var(--primary-color);
         font-weight: 600;
         display: flex;
         align-items: center;
         gap: 8px;
      }
      /* Scroll to Top Button */
      .scroll-top {
         position: fixed;
         bottom: 30px;
         right: 30px;
         background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
         color: white;
         width: 50px;
         height: 50px;
         border-radius: 50%;
         border: none;
         cursor: pointer;
         box-shadow: var(--shadow);
         transition: all 0.3s ease;
         opacity: 0;
         visibility: hidden;
         z-index: 999;
         display: flex;
         align-items: center;
         justify-content: center;
         font-size: 18px;
      }
      .scroll-top.visible {
         opacity: 1;
         visibility: visible;
      }
      .scroll-top:hover {
         transform: translateY(-5px) scale(1.1);
         box-shadow: 0 8px 25px rgba(52, 152, 219, 0.4);
      }
      /* Search Results */
      .search-results {
         position: absolute;
         top: 100%;
         left: 0;
         right: 0;
         background: var(--card-bg);
         border-radius: 8px;
         box-shadow: var(--shadow);
         max-height: 300px;
         overflow-y: auto;
         z-index: 1001;
         display: none;
         border: 1px solid var(--border-color);
      }
      .search-result {
         padding: 10px 15px;
         border-bottom: 1px solid var(--border-color);
         cursor: pointer;
         transition: background 0.2s ease;
         color: var(--text-color);
      }
      .search-result:hover {
         background: var(--primary-color);
         color: white;
      }
      .search-result:last-child {
         border-bottom: none;
      }
      /* Font Size Controls */
      .font-controls {
         display: flex;
         align-items: center;
         gap: 5px;
      }
      .font-btn {
         background: rgba(255,255,255,0.1);
         border: 1px solid rgba(255,255,255,0.2);
         color: white;
         width: 30px;
         height: 30px;
         border-radius: 50%;
         cursor: pointer;
         transition: all 0.3s ease;
         display: flex;
         align-items: center;
         justify-content: center;
      }
      .font-btn:hover {
         background: rgba(255,255,255,0.2);
      }
      /* Favorites */
      .favorite-btn {
         background: none;
         border: none;
         color: var(--text-muted);
         cursor: pointer;
         font-size: 1.2em;
         transition: all 0.3s ease;
         margin-left: 10px;
      }
      .favorite-btn:hover,
      .favorite-btn.favorited {
         color: var(--warning-color);
         transform: scale(1.2);
      }
      /* Tooltip */
      .tooltip {
         position: relative;
      }
      .tooltip .tooltiptext {
         visibility: hidden;
         background-color: var(--secondary-color);
         color: white;
         text-align: center;
         padding: 8px 12px;
         border-radius: 8px;
         position: absolute;
         z-index: 1000;
         bottom: 125%;
         left: 50%;
         margin-left: -100px;
         width: 200px;
         opacity: 0;
         transition: opacity 0.3s;
         font-size: 14px;
         font-weight: normal;
         box-shadow: var(--shadow);
      }
      .tooltip .tooltiptext::after {
         content: "";
         position: absolute;
         top: 100%;
         left: 50%;
         margin-left: -5px;
         border-width: 5px;
         border-style: solid;
         border-color: var(--secondary-color) transparent transparent transparent;
      }
      .tooltip:hover .tooltiptext {
         visibility: visible;
         opacity: 1;
      }
      /* Animations */
      @keyframes fadeInUp {
         from {
            opacity: 0;
            transform: translateY(30px);
         }
         to {
            opacity: 1;
            transform: translateY(0);
         }
      }
      @keyframes slideInLeft {
         from {
            opacity: 0;
            transform: translateX(-30px);
         }
         to {
            opacity: 1;
            transform: translateX(0);
         }
      }
      
      /* ===== MELHORIAS IMPLEMENTADAS ===== */
      
      /* 1. Melhorias na Acessibilidade */
      .skip-link {
         position: absolute;
         top: -40px;
         left: 0;
         background: var(--primary-color);
         color: white;
         padding: 8px;
         text-decoration: none;
         z-index: 100;
         border-radius: 0 0 4px 0;
      }
      
      .skip-link:focus {
         top: 0;
      }
      
      [data-theme="dark"] .term {
         background: rgba(231, 76, 60, 0.3);
      }
      
      [data-theme="dark"] .formula {
         background: linear-gradient(135deg, rgba(52, 152, 219, 0.2), rgba(52, 152, 219, 0.1));
         border-color: var(--primary-color);
      }
      
      [data-theme="dark"] .note {
         background: linear-gradient(135deg, rgba(243, 156, 18, 0.2), rgba(243, 156, 18, 0.1));
      }
      
      /* 4. Destaque de Texto Durante Leitura por Voz */
      .highlight-text {
         background-color: rgba(52, 152, 219, 0.4);
         padding: 2px 0;
         border-radius: 3px;
         transition: background-color 0.3s ease;
      }
      
      /* 5. Sistema de Tags para Anotações */
      .tags-filter {
         margin-bottom: 15px;
         padding: 10px;
         background: var(--bg-color);
         border-radius: 8px;
      }
      
      .tags-filter h4 {
         margin: 0 0 10px 0;
         font-size: 0.9em;
         color: var(--text-color);
      }
      
      .tag-button {
         background: var(--primary-color);
         color: white;
         border: none;
         padding: 5px 10px;
         border-radius: 15px;
         margin: 0 5px 5px 0;
         cursor: pointer;
         font-size: 0.8em;
         transition: all 0.3s ease;
      }
      
      .tag-button:hover {
         background: var(--secondary-color);
         transform: translateY(-2px);
      }
      
      .tag-button.active {
         background: var(--accent-color);
      }
      
      .tag-button.clear {
         background: var(--text-muted);
      }
      
      .nota-tags {
         margin: 5px 0;
      }
      
      .tag {
         display: inline-block;
         background-color: var(--primary-color);
         color: white;
         padding: 2px 8px;
         border-radius: 12px;
         font-size: 0.8em;
         margin-right: 5px;
      }
      
      /* 6. Modo de Estudo com Flashcards */
      .flashcard-container {
         display: flex;
         justify-content: center;
         align-items: center;
         height: 100%;
         padding: 20px;
      }
      
      .flashcard {
         width: 100%;
         max-width: 600px;
         height: 300px;
         perspective: 1000px;
         cursor: pointer;
      }
      
      .flashcard-front, .flashcard-back {
         position: absolute;
         width: 100%;
         height: 100%;
         backface-visibility: hidden;
         border-radius: 12px;
         box-shadow: var(--shadow);
         display: flex;
         flex-direction: column;
         justify-content: center;
         align-items: center;
         padding: 20px;
         text-align: center;
         transition: transform 0.6s;
         background: var(--card-bg);
      }
      
      .flashcard-back {
         transform: rotateY(180deg);
      }
      
      .flashcard-actions {
         display: flex;
         justify-content: center;
         gap: 15px;
         flex-wrap: wrap;
      }
      
      .flashcard-actions button {
         padding: 8px 16px;
         border-radius: 6px;
         border: none;
         cursor: pointer;
         font-weight: 600;
         transition: all 0.3s ease;
      }
      
      .flashcard-actions button:nth-child(1) {
         background: var(--success-color);
         color: white;
      }
      
      .flashcard-actions button:nth-child(2) {
         background: var(--warning-color);
         color: white;
      }
      
      .flashcard-actions button:nth-child(3) {
         background: var(--accent-color);
         color: white;
      }
      
      .flashcard-actions button:nth-child(4) {
         background: var(--primary-color);
         color: white;
      }
      
      .flashcard-actions button:hover {
         transform: translateY(-2px);
         box-shadow: var(--shadow);
      }
      
      /* 7. Indicador de Progresso Visual */
      .section.read {
         opacity: 0.8;
         border-left: 4px solid var(--success-color);
      }
      
      .read-indicator {
         display: inline-block;
         margin-left: 10px;
         color: var(--success-color);
         font-size: 0.8em;
      }
      
      .progress-indicator {
         margin: 15px 0;
         padding: 10px;
         background: var(--bg-color);
         border-radius: 8px;
         font-size: 0.9em;
      }
      
      .progress-text {
         margin-bottom: 5px;
         color: var(--text-color);
      }
      
      .progress-bar-container {
         height: 8px;
         background: var(--border-color);
         border-radius: 4px;
         overflow: hidden;
      }
      
      .progress-bar-fill {
         height: 100%;
         background: linear-gradient(90deg, var(--primary-color), var(--success-color));
         transition: width 0.3s ease;
      }
      
      /* 9. Exportação de Anotações */
      .export-options {
         margin-top: 20px;
         padding: 15px;
         background: var(--bg-color);
         border-radius: 8px;
      }
      
      .export-options h4 {
         margin: 0 0 10px 0;
         color: var(--primary-color);
      }
      
      .export-options button {
         margin: 5px;
         padding: 8px 12px;
         border-radius: 4px;
         border: none;
         background: var(--primary-color);
         color: white;
         cursor: pointer;
         transition: all 0.3s ease;
      }
      
      .export-options button:hover {
         background: var(--secondary-color);
         transform: translateY(-2px);
      }
      
      /* 10. Modo de Impressão Otimizado */
      @media print {
         .header, .sidebar, .tools-sidebar, .scroll-top, .fullscreen-btn, 
         .speed-control, .bookmark-list, .reading-stats, .share-menu, .presentation-controls, .exit-focus-btn, .header-toggle-btn,
         .favorite-btn, .bookmark-btn, .open-popup-btn, .section-note-btn,
         .progress-bar, .search-container, .font-controls, .header-controls,
         .term .tooltiptext, .image-placeholder, .comparison-item,
         .nota-acoes button, .export-options, .tags-filter {
            display: none !important;
         }
         
         body {
            padding: 0 !important;
            background: white !important;
            color: black !important;
            font-size: 12pt !important;
            line-height: 1.5 !important;
         }
         
         .container {
            box-shadow: none !important;
            margin: 0 !important;
            max-width: none !important;
            padding: 0 !important;
            border: none !important;
         }
         
         .section {
            page-break-inside: avoid;
            margin-bottom: 20pt !important;
            padding: 10pt !important;
            border: 1pt solid #ddd !important;
            border-radius: 0 !important;
         }
         
         h2, h3, h4, h5 {
            page-break-after: avoid;
            margin-top: 10pt !important;
            margin-bottom: 5pt !important;
         }
         
         h2 {
            font-size: 16pt !important;
            border-bottom: 1pt solid #ddd !important;
            padding-bottom: 5pt !important;
            color: black !important;
            background: none !important;
         }
         
         h3 {
            font-size: 14pt !important;
            color: black !important;
         }
         
         h4 {
            font-size: 12pt !important;
            color: black !important;
         }
         
         h5 {
            font-size: 11pt !important;
            color: black !important;
         }
         
         p {
            margin-bottom: 8pt !important;
            orphans: 3;
            widows: 3;
         }
         
         .formula, .note {
            page-break-inside: avoid;
            padding: 10pt !important;
            border: 1pt solid #ddd !important;
            background: none !important;
         }
         
         .formula {
            font-style: italic;
            text-align: center;
         }
         
         .note h4 {
            color: black !important;
         }
         
         .comparison {
            display: block !important;
         }
         
         .comparison-item {
            page-break-inside: avoid;
            margin-bottom: 10pt !important;
            padding: 10pt !important;
            border: 1pt solid #ddd !important;
         }
         
         .bibliography-item {
            margin-bottom: 5pt !important;
         }
         
         .term {
            background: none !important;
            color: black !important;
            padding: 0 !important;
            border-bottom: 1pt dotted #333 !important;
            border-radius: 0 !important;
         }
         
         .read-indicator {
            display: none !important;
         }
         
         @page {
            margin: 2cm;
            
            @top-center {
               content: "Noções de Eletricidade e Equipamento Gerador de Raios X";
               font-size: 10pt;
            }
            
            @bottom-center {
               content: "Página " counter(page) " de " counter(pages);
               font-size: 10pt;
            }
         }
         
         .section:not(:first-child) {
            page-break-before: always;
         }
         
         img {
            max-width: 100% !important;
            height: auto !important;
            page-break-inside: avoid;
         }
         
         .bibliography {
            margin-top: 20pt !important;
         }
         
         .bibliography h2 {
            background: none !important;
            color: black !important;
            border-left: none !important;
            padding-left: 0 !important;
         }
      }
      
      /* ===== FIM DAS MELHORIAS IMPLEMENTADAS ===== */
      
      /* Responsive */
      @media (max-width: 768px) {
         body {
            padding: 10px 10px 20px 10px;
         }
         .header {
            padding: 8px 15px;
         }
         .header h1 {
            font-size: 0.9em;
         }
         .container {
            padding: 20px;
            margin: 0;
            border-radius: 0;
         }
         .sidebar, .tools-sidebar {
            width: 280px;
            left: -300px;
         }
         .tools-sidebar {
            right: -300px;
         }
         .search-container {
            max-width: 150px;
         }
         .comparison {
            grid-template-columns: 1fr;
         }
         .fullscreen-btn {
            width: 32px;
            height: 32px;
            font-size: 14px;
         }
         .tools-grid {
            grid-template-columns: 1fr;
         }
         body.presentation-mode .section {
            padding: 30px 20px;
         }
         body.presentation-mode .section h2 {
            font-size: 2em;
         }
         body.presentation-mode .section p {
            font-size: 1.2em;
         }
         .presentation-controls {
            padding: 0 20px;
         }
         .presentation-controls button {
            padding: 8px 12px;
            font-size: 14px;
         }
         .slide-counter {
            font-size: 14px;
            padding: 6px 12px;
         }
         .presentation-progress {
            width: 200px;
         }
      }
      
      /* Popup styles */
      button { margin: 5px; padding: 8px 14px; cursor: pointer; border-radius: 4px; border: none; background: #1976d2; color: #fff; font-size: 0.5em; }
      button:hover { background: #125a9c; }
      #popup {
         display: none;
         position: fixed;
         top: 0; left: 0; width: 100%; height: 100%;
         background: rgba(0,0,0,0.6);
         justify-content: center; align-items: center;
         padding: 10px;
         box-sizing: border-box;
         z-index: 10000;
      }
      #popup-content {
         background: #fff; padding: 20px; width: 500px;
         max-height: 90%; overflow-y: auto;
         border-radius: 8px; position: relative;
      }
      #fecharPopup {
         position: absolute; top: 10px; right: 10px;
         background: red; color: #fff; border: none; padding: 5px 10px;
         cursor: pointer; border-radius: 4px; font-size: 1em;
      }
      .nota { 
         border-bottom: 1px solid #ccc; 
         padding: 10px 0; 
         display: flex;
         justify-content: space-between;
         align-items: center;
         font-size: 0.95em;
      }
      .nota-info { flex-grow: 1; }
      .nota-acoes { margin-left: 10px; }
      .nota h3 { margin: 0; font-size: 1.1em; }
      .nota small { font-size: 0.85em; }
      textarea { width: 100%; height: 100px; padding: 5px; font-size: 0.9em; }
      input[type="text"], input[type="datetime-local"] {
         width: 100%; padding: 8px; margin-bottom: 10px; box-sizing: border-box; font-size: 0.9em;
      }
      #listing-container {
         display: block;
      }
      #form-container {
         display: none;
      }
      /* Estilos para o popup da seção */
      .section-popup {
         display: none;
         position: fixed;
         top: 0;
         left: 0;
         width: 100%;
         height: 100%;
         z-index: 10001;
      }
      .section-popup-overlay {
         position: absolute;
         top: 0;
         left: 0;
         width: 100%;
         height: 100%;
         background-color: rgba(0, 0, 0, 0.7);
      }
      .section-popup-content {
         position: relative;
         width: 90%;
         max-width: 800px;
         height: 90%;
         margin: 5% auto;
         background-color: var(--card-bg);
         border-radius: 12px;
         box-shadow: var(--shadow);
         display: flex;
         flex-direction: column;
         overflow: hidden;
      }
      .section-popup-header {
         padding: 15px 20px;
         background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
         color: white;
         display: flex;
         justify-content: space-between;
         align-items: center;
      }
      .section-popup-header h3 {
         margin: 0;
         font-size: 1.2em;
      }
      .section-popup-controls {
         display: flex;
         align-items: center;
         gap: 10px;
      }
      .section-popup-btn {
         background: rgba(255, 255, 255, 0.2);
         border: 1px solid rgba(255, 255, 255, 0.3);
         color: white;
         width: 36px;
         height: 36px;
         border-radius: 50%;
         cursor: pointer;
         transition: all 0.3s ease;
         display: flex;
         align-items: center;
         justify-content: center;
         font-size: 16px;
      }
      .section-popup-btn:hover {
         background: rgba(255, 255, 255, 0.3);
         transform: scale(1.1);
      }
      .section-popup-btn:disabled {
         opacity: 0.5;
         cursor: not-allowed;
      }
      #zoomLevel {
         min-width: 50px;
         text-align: center;
      }
      .section-popup-body {
         flex: 1;
         padding: 20px;
         overflow-y: auto;
         font-size: 100%; /* Será ajustado pelo zoom */
      }
      .section-popup-footer {
         padding: 10px 20px;
         background: var(--bg-color);
         border-top: 1px solid var(--border-color);
         display: flex;
         justify-content: center;
         gap: 15px;
      }
      /* Estilos para os controles de áudio no popup da seção */
      .section-audio-controls {
         display: flex;
         align-items: center;
         gap: 8px;
         margin-top: 15px;
         padding: 10px;
         background: rgba(52, 152, 219, 0.1);
         border-radius: 8px;
         border: 1px solid rgba(52, 152, 219, 0.2);
      }
      .section-audio-controls h4 {
         margin: 0;
         font-size: 0.9em;
         color: var(--primary-color);
      }
      .section-audio-buttons {
         display: flex;
         gap: 4px;
      }
      .section-audio-buttons button {
         background: rgba(52, 152, 219, 0.2);
         border: 1px solid rgba(52, 152, 219, 0.3);
         color: var(--primary-color);
         width: 32px;
         height: 32px;
         border-radius: 50%;
         cursor: pointer;
         transition: all 0.3s ease;
         display: flex;
         align-items: center;
         justify-content: center;
         font-size: 0.9em;
      }
      .section-audio-buttons button:hover:not(:disabled) {
         background: rgba(52, 152, 219, 0.3);
         transform: scale(1.1);
      }
      .section-audio-buttons button:disabled {
         background: rgba(52, 152, 219, 0.1);
         cursor: not-allowed;
         opacity: 0.6;
      }
      .open-popup-btn {
         background: none;
         border: none;
         color: white;
         cursor: pointer;
         font-size: 1em;
         margin-left: 10px;
         transition: all 0.3s ease;
      }
      .open-popup-btn:hover {
         transform: scale(1.2);
      }
      
      /* Estilos para o modo tela cheia do popup da seção */
      .section-popup.fullscreen-mode {
         width: 100% !important;
         height: 100% !important;
         max-width: none !important;
         max-height: none !important;
         margin: 0 !important;
         border-radius: 0 !important;
      }
      
      .section-popup.fullscreen-mode .section-popup-body {
         height: calc(100% - 120px) !important;
      }
      
      .section-popup.fullscreen-mode .section-popup-footer {
         padding: 15px 20px;
         background: rgba(0, 0, 0, 0.8);
         border-top: 1px solid rgba(255, 255, 255, 0.2);
         display: flex;
         justify-content: space-between;
         align-items: center;
      }
      
      .section-popup.fullscreen-mode .section-audio-controls {
         background: rgba(52, 152, 219, 0.2);
         border: 1px solid rgba(52, 152, 219, 0.4);
      }
      
      .section-popup.fullscreen-mode .section-popup-controls {
         background: rgba(0, 0, 0, 0.5);
         padding: 5px;
         border-radius: 8px;
      }
      
      .section-popup.fullscreen-mode .section-popup-header {
         background: linear-gradient(135deg, rgba(52, 152, 219, 0.9), rgba(44, 62, 80, 0.9));
         backdrop-filter: blur(10px);
      }
      
      /* Estilos para o botão de anotações da seção */
      .section-note-btn {
         background: none;
         border: none;
         color: var(--text-muted);
         cursor: pointer;
         font-size: 1.2em;
         transition: all 0.3s ease;
         margin-left: 10px;
      }
      
      .section-note-btn:hover,
      .section-note-btn.has-notes {
         color: var(--warning-color);
         transform: scale(1.2);
      }
      
      /* Estilos para o popup de anotações da seção */
      #sectionNotePopup .section-popup-body {
         padding: 20px;
      }
      
      #sectionNotePopup .nota {
         border-bottom: 1px solid var(--border-color);
         padding: 15px 0;
         margin-bottom: 10px;
      }
      
      #sectionNotePopup .nota h4 {
         margin: 0 0 5px 0;
         color: var(--primary-color);
      }
      
      #sectionNotePopup .nota small {
         color: var(--text-muted);
         font-size: 0.8em;
      }
      
      #sectionNotePopup .nota p {
         margin: 10px 0 0 0;
         white-space: pre-wrap;
      }
      
      #sectionNotePopup .nota-acoes {
         margin-top: 10px;
      }
      
      #sectionNotePopup .nota-acoes button {
         margin-right: 5px;
         padding: 5px 10px;
         font-size: 0.8em;
      }