/* =====================================================
   FICHA DE EXERCÍCIOS - VERSÃO 2.0 OTIMIZADA
   Responsive, Acessível, Performance Otimizada
   ===================================================== */

/* =====================================================
   1. CSS CUSTOM PROPERTIES (VARIÁVEIS)
   ===================================================== */
:root {
    /* Cores principais */
    --ficha-bg: #f5f5f5;
    --ficha-paper: #ffffff;
    --ficha-text: #000000;
    --ficha-text-secondary: #333333;
    --ficha-text-muted: #666666;
    --ficha-border: #cccccc;
    --ficha-border-light: #eeeeee;
    
    /* Cores de ação */
    --btn-resolucao-bg: #e0f2fe;
    --btn-resolucao-border: #0ea5e9;
    --btn-resolucao-text: #0369a1;
    --btn-resolucao-hover: #bae6fd;
    
    --btn-video-bg: #fef3c7;
    --btn-video-border: #f59e0b;
    --btn-video-text: #92400e;
    --btn-video-hover: #fde68a;
    
    --btn-danger-bg: #dc2626;
    --btn-danger-text: #ffffff;
    
    /* Espaçamentos */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 0.75rem;
    --spacing-lg: 1rem;
    --spacing-xl: 1.5rem;
    --spacing-2xl: 2rem;
    
    /* Tipografia */
    --font-serif: 'Times New Roman', Times, serif;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-base: 12pt;
    --font-size-sm: 10pt;
    --font-size-xs: 9pt;
    --line-height: 1.6;
    
    /* Bordas */
    --radius-sm: 4px;
    --radius-md: 6px;
    --radius-lg: 8px;
    
    /* Sombras */
    --shadow-paper: 0 4px 12px rgba(0, 0, 0, 0.15);
    
    /* Touch targets */
    --touch-target-min: 48px;
    --touch-target-sm: 44px;
    
    /* Transições */
    --transition-fast: 150ms ease;
    --transition-normal: 200ms ease;
    --transition-slow: 300ms ease;
    
    /* Z-index layers */
    --z-base: 1;
    --z-dropdown: 100;
    --z-modal: 9999;
}

/* =====================================================
   2. RESET E BASE
   ===================================================== */
.ficha-container *,
.ficha-container *::before,
.ficha-container *::after {
    box-sizing: border-box;
}

/* ========================================
   FORÇAR MODO CLARO APENAS NO DOCUMENTO PDF
   NÃO AFETA HEADER/NAVEGAÇÃO DA PLATAFORMA
   ======================================== */

/* Forçar documento PDF sempre claro */
.pdf-document {
    color-scheme: light !important;
    background-color: #ffffff !important;
}

/* Sobrepor dark mode do sistema APENAS no documento */
.pdf-document,
.pdf-document *,
.pdf-header,
.pdf-header *,
.pdf-title,
.pdf-title *,
.pdf-content,
.pdf-content *,
.exercicio,
.exercicio *,
.alinea,
.alinea * {
    color-scheme: light !important;
    forced-color-adjust: none !important;
}

/* Forçar texto preto no documento PDF */
.pdf-document {
    color: #000000 !important;
    -webkit-text-fill-color: #000000 !important;
}

.pdf-institution h3,
.pdf-year,
.pdf-subject p,
.pdf-title h1,
.pdf-title h2,
.exercicio-numero,
.exercicio-enunciado-geral,
.alinea-letra,
.alinea-texto {
    color: #000000 !important;
    -webkit-text-fill-color: #000000 !important;
}

/* Bloquear dark mode em botões dentro do PDF */
.btn-toggle-resolucao,
.btn-video {
    forced-color-adjust: none !important;
}

/* Garantir fundo branco mesmo com tema escuro ativo */
body.dark-theme .pdf-document,
[data-theme="dark"] .pdf-document,
@media (prefers-color-scheme: dark) {
    .pdf-document {
        background-color: #ffffff !important;
        color: #000000 !important;
    }
}

/* =====================================================
   3. CONTAINER PRINCIPAL
   ===================================================== */
.ficha-container {
    background: var(--ficha-bg);
    min-height: 100vh;
    padding: var(--spacing-2xl) var(--spacing-lg);
}

/* =====================================================
   4. CABEÇALHO DA PÁGINA (AÇÕES)
   ===================================================== */
.ficha-page-header {
    max-width: 210mm;
    margin: 0 auto var(--spacing-xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: #fff;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.83rem;
    font-family: var(--font-sans);
    padding: 7px 16px;
    border-radius: 999px;
    background: #4f46e5;
    border: none;
    transition: background var(--transition-fast), transform var(--transition-fast);
    white-space: nowrap;
}

.back-link:hover {
    text-decoration: none;
    background: #4338ca;
    transform: translateX(-2px);
    color: #fff;
}

.back-link:focus-visible {
    outline: 2px solid #4f46e5;
    outline-offset: 2px;
}

.ficha-actions-top {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.ficha-actions-top .btn {
    font-family: var(--font-sans);
    min-height: var(--touch-target-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
}

/* =====================================================
   5. DOCUMENTO PDF (FORMATO A4)
   ===================================================== */
.pdf-document {
    width: 210mm;
    min-height: 297mm;
    margin: 0 auto;
    background: var(--ficha-paper);
    box-shadow: var(--shadow-paper);
    padding: 25mm 20mm;
    font-family: var(--font-serif);
    font-size: var(--font-size-base);
    line-height: var(--line-height);
    color: var(--ficha-text);
    position: relative;
}

/* =====================================================
   6. CABEÇALHO DO DOCUMENTO
   ===================================================== */
.pdf-header {
    border-bottom: 2px solid var(--ficha-text);
    padding-bottom: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.pdf-header-top {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.pdf-institution h3 {
    font-size: 14pt;
    font-weight: bold;
    margin: 0 0 var(--spacing-xs) 0;
    color: var(--ficha-text);
}

.pdf-institution p,
.pdf-year {
    font-size: var(--font-size-sm);
    margin: 0;
    color: var(--ficha-text-secondary);
}

.pdf-subject {
    text-align: right;
    flex-shrink: 0;
}

.pdf-subject p {
    margin: var(--spacing-xs) 0;
    font-size: var(--font-size-sm);
    color: var(--ficha-text);
}

/* =====================================================
   7. TÍTULO DA FICHA
   ===================================================== */
.pdf-title {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.pdf-title h1 {
    font-size: 18pt;
    font-weight: bold;
    margin: 0 0 var(--spacing-sm) 0;
    text-transform: uppercase;
    color: var(--ficha-text);
    letter-spacing: 1px;
}

.pdf-title h2 {
    font-size: 14pt;
    font-weight: normal;
    margin: 0;
    color: var(--ficha-text);
}

/* =====================================================
   8. DESCRIÇÃO
   ===================================================== */
.pdf-description {
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-md) var(--spacing-lg);
    background: #f9f9f9;
    border-left: 3px solid var(--ficha-text-muted);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.pdf-description p {
    margin: 0;
    font-size: 11pt;
    color: var(--ficha-text-secondary);
}

/* =====================================================
   9. SEPARADOR
   ===================================================== */
.pdf-separator {
    height: 1px;
    background: var(--ficha-border);
    margin: var(--spacing-xl) 0;
}

/* =====================================================
   10. CONTEÚDO PRINCIPAL
   ===================================================== */
.pdf-content {
    margin-bottom: 3rem;
}

/* =====================================================
   11. EXERCÍCIOS
   ===================================================== */
.exercicio {
    margin-bottom: var(--spacing-2xl);
    page-break-inside: avoid;
}

.exercicio-header {
    display: flex;
    align-items: baseline;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
}

.exercicio-numero {
    font-weight: bold;
    font-size: 13pt;
    color: var(--ficha-text);
    min-width: 2rem;
    flex-shrink: 0;
}

.exercicio-enunciado-geral {
    flex: 1;
    font-size: var(--font-size-base);
    color: var(--ficha-text);
    min-width: 200px;
}

.exercicio-pontuacao {
    font-size: var(--font-size-sm);
    color: var(--ficha-text-muted);
    font-style: italic;
    flex-shrink: 0;
}

/* =====================================================
   12. ALÍNEAS
   ===================================================== */
.alineas-container {
    margin-left: 2rem;
}

.alinea {
    margin-bottom: var(--spacing-xl);
    page-break-inside: avoid;
}

.alinea-enunciado {
    display: flex;
    align-items: baseline;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    flex-wrap: wrap;
}

.alinea-letra {
    font-weight: bold;
    font-size: 11pt;
    color: var(--ficha-text);
    min-width: 1.5rem;
    flex-shrink: 0;
}

.alinea-texto {
    flex: 1;
    font-size: 11pt;
    color: var(--ficha-text);
    min-width: 0; /* Permite quebra de linha */
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.alinea-pontuacao {
    font-size: var(--font-size-sm);
    color: var(--ficha-text-muted);
    font-style: italic;
    flex-shrink: 0;
}

/* =====================================================
   13. ESPAÇO PARA RESOLUÇÃO (IMPRESSÃO)
   ===================================================== */
.espaco-resolucao {
    display: none;
}

/* =====================================================
   14. CONTAINER DE AÇÕES (BOTÕES)
   ===================================================== */
.alinea-actions {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
    clear: both;
}

/* =====================================================
   15. BOTÕES BASE
   ===================================================== */
.btn-toggle-resolucao,
.btn-video {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-family: var(--font-sans);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: 1px solid var(--ficha-border);
    background: #f0f0f0;
    color: var(--ficha-text);
    
    /* Touch improvements */
    -webkit-tap-highlight-color: rgba(0, 0, 0, 0.1);
    user-select: none;
    -webkit-user-select: none;
    touch-action: manipulation;
    
    /* Acessibilidade */
    min-height: var(--touch-target-sm);
}

.btn-toggle-resolucao:hover,
.btn-video:hover {
    background: #e0e0e0;
}

.btn-toggle-resolucao:active,
.btn-video:active {
    transform: scale(0.98);
    background: #d0d0d0;
}

.btn-toggle-resolucao:focus-visible,
.btn-video:focus-visible {
    outline: 2px solid var(--btn-resolucao-border);
    outline-offset: 2px;
}

/* =====================================================
   16. CONTAINERS DE RESOLUÇÃO E VÍDEO
   ===================================================== */
.resolucao-container,
.video-container {
    margin-top: 0;
}

/* =====================================================
   17. CONTEÚDO DA RESOLUÇÃO
   ===================================================== */
.resolucao-content {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: #f9f9f9;
    border-left: 3px solid #4a90e2;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    animation: slideDown var(--transition-normal) ease-out;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.resolucao-header {
    font-weight: bold;
    margin-bottom: var(--spacing-sm);
    color: #4a90e2;
    font-family: var(--font-sans);
}

.resolucao-texto {
    font-size: 11pt;
    color: var(--ficha-text-secondary);
    white-space: pre-wrap;
    line-height: var(--line-height);
}

/* =====================================================
   18. PLAYER DE VÍDEO
   ===================================================== */
.video-player {
    margin-top: var(--spacing-lg);
    animation: slideDown var(--transition-normal) ease-out;
}

.video-wrapper {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 */
    height: 0;
    overflow: hidden;
    border-radius: var(--radius-lg);
    background: #000;
}

.video-wrapper iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

/* Placeholder para lazy loading */
.video-wrapper[data-loading]::before {
    content: '🎬 Carregando vídeo...';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-family: var(--font-sans);
}

.btn-close-video {
    margin-top: var(--spacing-sm);
    background: var(--btn-danger-bg);
    color: var(--btn-danger-text);
    border: none;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: var(--font-size-sm);
    font-family: var(--font-sans);
    min-height: var(--touch-target-sm);
    transition: background var(--transition-fast);
}

.btn-close-video:hover {
    background: #b91c1c;
}

.btn-close-video:focus-visible {
    outline: 2px solid var(--btn-danger-bg);
    outline-offset: 2px;
}

/* =====================================================
   19. RODAPÉ
   ===================================================== */
.pdf-footer {
    position: absolute;
    bottom: 15mm;
    left: 20mm;
    right: 20mm;
    border-top: 1px solid var(--ficha-border);
    padding-top: var(--spacing-md);
    text-align: center;
}

.pdf-footer-text {
    font-size: var(--font-size-xs);
    color: var(--ficha-text-muted);
    margin: 0 0 var(--spacing-xs) 0;
}

.pdf-footer-meta {
    font-size: 8pt;
    color: #999;
    margin: 0;
}

/* =====================================================
   20. MENSAGENS VAZIAS
   ===================================================== */
.no-exercicios,
.no-alineas {
    text-align: center;
    padding: var(--spacing-2xl);
    color: var(--ficha-text-muted);
    font-size: 11pt;
}

/* =====================================================
   21. FÓRMULAS MATEMÁTICAS (KaTeX)
   ===================================================== */
.katex-display {
    overflow-x: auto;
    overflow-y: hidden;
    -webkit-overflow-scrolling: touch;
    padding: var(--spacing-sm) 0;
    margin: var(--spacing-sm) 0;
}

/* Scroll indicator for formulas */
.katex-display::-webkit-scrollbar {
    height: 4px;
}

.katex-display::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 2px;
}

.katex-display::-webkit-scrollbar-thumb {
    background: #ccc;
    border-radius: 2px;
}

/* =====================================================
   22. MODAL DE VÍDEO
   ===================================================== */
.video-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.9);
    z-index: var(--z-modal);
    align-items: center;
    justify-content: center;
    animation: fadeIn var(--transition-fast);
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.video-modal-content {
    position: relative;
    width: 95%;
    max-width: 800px;
    background: #000;
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.video-modal-close {
    position: absolute;
    top: -45px;
    right: 0;
    background: none;
    border: none;
    color: white;
    font-size: 28px;
    cursor: pointer;
    padding: 8px;
    z-index: 10;
    min-width: var(--touch-target-min);
    min-height: var(--touch-target-min);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform var(--transition-fast);
}

.video-modal-close:hover {
    transform: scale(1.1);
}

.video-modal-wrapper {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
}

.video-modal-wrapper iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

/* =====================================================
   22.5. MODAL DE RESOLUÇÃO
   ===================================================== */
.resolucao-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    z-index: var(--z-modal);
    align-items: center;
    justify-content: center;
    padding: 20px;
    box-sizing: border-box;
    animation: fadeIn var(--transition-fast);
}

.resolucao-modal.is-open {
    display: flex;
}

.resolucao-modal-content {
    position: relative;
    width: 100%;
    max-width: 800px;
    max-height: 90vh;
    background: #ffffff;
    border-radius: var(--radius-lg);
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.3);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.resolucao-modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    background: linear-gradient(135deg, #4a90d9 0%, #357abd 100%);
    color: white;
    flex-shrink: 0;
}

.resolucao-modal-header h2 {
    margin: 0;
    font-size: 1.25rem;
    font-weight: 600;
}

.resolucao-modal-close {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    font-size: 20px;
    cursor: pointer;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    min-width: var(--touch-target-min);
    min-height: var(--touch-target-min);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background var(--transition-fast);
}

.resolucao-modal-close:hover {
    background: rgba(255, 255, 255, 0.3);
}

.resolucao-modal-body {
    padding: 24px;
    overflow-y: auto;
    flex-grow: 1;
    background: #ffffff;
    color: #1a1a1a;
    font-size: 1rem;
    line-height: 1.7;
}

/* Estilos para o conteúdo dentro do modal */
.resolucao-modal-body p {
    margin-bottom: 1em;
    color: #1a1a1a;
}

.resolucao-modal-body .katex {
    font-size: 1.1em;
}

.resolucao-modal-body .katex-display {
    margin: 1em 0;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 10px 0;
}

/* Mobile responsivo */
@media (max-width: 768px) {
    .resolucao-modal {
        padding: 10px;
    }
    
    .resolucao-modal-content {
        max-height: 95vh;
        border-radius: var(--radius-md);
    }
    
    .resolucao-modal-header {
        padding: 12px 16px;
    }
    
    .resolucao-modal-header h2 {
        font-size: 1.1rem;
    }
    
    .resolucao-modal-body {
        padding: 16px;
        font-size: 0.95rem;
    }
    
    .resolucao-modal-body .katex {
        font-size: 1em;
    }
}

/* =====================================================
   23. IMPRESSÃO
   ===================================================== */
@media print {
    body {
        background: white;
    }

    .ficha-container {
        background: white;
        padding: 0;
    }

    .ficha-page-header {
        display: none !important;
    }

    .pdf-document {
        width: 100%;
        margin: 0;
        box-shadow: none;
        padding: 15mm;
        min-height: auto;
    }

    /* Esconder botões e elementos interativos */
    .alinea-actions,
    .btn-toggle-resolucao,
    .btn-video,
    .btn-close-video,
    .resolucao-container,
    .video-container,
    .video-modal {
        display: none !important;
    }

    /* Mostrar espaço para resolução */
    .espaco-resolucao {
        display: block;
        min-height: 50mm;
        border: 1px dashed #ccc;
        margin-top: var(--spacing-lg);
    }

    /* Evitar quebras de página indesejadas */
    .exercicio,
    .alinea {
        page-break-inside: avoid;
    }

    /* Footer fixo */
    .pdf-footer {
        position: fixed;
        bottom: 0;
    }
}

/* =====================================================
   24. RESPONSIVO - TABLET (≤ 1024px)
   ===================================================== */
@media (max-width: 1024px) {
    .pdf-document {
        width: 100%;
        max-width: 210mm;
        padding: 20mm 15mm;
    }
}

/* =====================================================
   25. RESPONSIVO - MOBILE (≤ 768px)
   ===================================================== */
@media (max-width: 768px) {
    /* Prevenir scroll horizontal */
    html, body {
        overflow-x: hidden;
        width: 100%;
    }
    
    /* Container - fundo cinza para contrastar com o papel */
    .ficha-container {
        padding: var(--spacing-md);
        background: #e8e8e8 !important;
        background-color: #e8e8e8 !important;
        min-height: 100vh;
        color-scheme: light !important;
    }

    /* === CABEÇALHO DA PÁGINA (UI - não é parte do PDF) === */
    .ficha-page-header {
        flex-direction: column;
        align-items: stretch;
        padding: var(--spacing-md);
        margin: 0 0 var(--spacing-md) 0;
        background: #ffffff;
        border-radius: var(--radius-lg);
        box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
        gap: var(--spacing-sm);
        max-width: none;
    }
    
    .back-link {
        font-size: 14px;
        display: block;
        padding: var(--spacing-sm) 0;
    }

    .ficha-actions-top {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
        gap: var(--spacing-sm);
    }
    
    .ficha-actions-top .btn,
    .ficha-actions-top a {
        font-size: 12px;
        padding: var(--spacing-sm) var(--spacing-md);
        text-align: center;
        white-space: nowrap;
        min-height: var(--touch-target-sm);
        display: flex;
        align-items: center;
        justify-content: center;
    }

    /* ========================================
       DOCUMENTO PDF - ESTILO PAPEL REAL
       ======================================== */
    .pdf-document {
        /* Dimensões */
        width: calc(100% - 8px);
        min-height: auto;
        margin: 4px auto;
        
        /* Aparência de papel - FORÇAR BRANCO */
        background: #ffffff !important;
        background-color: #ffffff !important;
        box-shadow: 
            0 2px 8px rgba(0, 0, 0, 0.15),
            0 1px 3px rgba(0, 0, 0, 0.1);
        border: 1px solid #d0d0d0;
        border-radius: 2px;
        
        /* Margens internas de documento */
        padding: 20mm 12mm 15mm 12mm;
        
        /* Tipografia de documento - FORÇAR PRETO */
        font-family: var(--font-serif);
        font-size: 10.5pt;
        line-height: 1.6;
        color: #000000 !important;
        
        /* Forçar modo claro */
        color-scheme: light !important;
        -webkit-text-fill-color: #000000 !important;
    }

    /* === CABEÇALHO DO DOCUMENTO (Instituição) === */
    .pdf-header {
        flex-direction: column;
        gap: var(--spacing-sm);
        padding-bottom: var(--spacing-md);
        margin-bottom: var(--spacing-lg);
        border-bottom: 1.5px solid #2c2c2c;
    }
    
    .pdf-institution h3 {
        font-size: 11pt;
        font-weight: 700;
        margin-bottom: 2px;
        color: #1a1a1a;
        letter-spacing: 0.3px;
    }
    
    .pdf-year {
        font-size: 8.5pt;
        color: #4a4a4a;
        margin: 0;
    }

    .pdf-subject {
        text-align: left;
        margin-top: var(--spacing-sm);
        padding-top: var(--spacing-sm);
        border-top: 1px solid #e5e5e5;
    }
    
    .pdf-subject p {
        font-size: 9pt;
        margin: 2px 0;
        color: #2c2c2c;
    }

    /* === TÍTULO DA FICHA === */
    .pdf-title {
        margin: var(--spacing-lg) 0;
        padding: var(--spacing-md) 0;
    }
    
    .pdf-title h1 {
        font-size: 12pt;
        font-weight: 700;
        letter-spacing: 1.5px;
        text-transform: uppercase;
        color: #1a1a1a;
        margin-bottom: var(--spacing-xs);
    }
    
    .pdf-title h2 {
        font-size: 10pt;
        font-weight: 400;
        color: #3a3a3a;
    }

    /* === DESCRIÇÃO === */
    .pdf-description {
        margin: var(--spacing-md) 0 var(--spacing-lg) 0;
        padding: var(--spacing-sm) var(--spacing-md);
        background: #fafafa;
        border-left: 2px solid #6b7280;
        font-size: 9pt;
        color: #4b5563;
    }

    /* === CONTEÚDO PRINCIPAL === */
    .pdf-content {
        margin-bottom: var(--spacing-lg);
    }

    /* === EXERCÍCIOS (Estilo académico) === */
    .exercicio {
        margin-bottom: var(--spacing-xl);
        padding-bottom: var(--spacing-md);
        border-bottom: 1px solid #e5e5e5;
    }
    
    .exercicio:last-child {
        border-bottom: none;
    }
    
    .exercicio-header {
        flex-wrap: wrap;
        gap: var(--spacing-xs);
        margin-bottom: var(--spacing-sm);
        align-items: baseline;
    }
    
    .exercicio-numero {
        font-size: 10.5pt;
        font-weight: 700;
        min-width: auto;
        color: #1a1a1a;
    }
    
    .exercicio-enunciado-geral {
        font-size: 10pt;
        flex: 1;
        min-width: 0;
        color: #2c2c2c;
        line-height: 1.5;
    }
    
    .exercicio-pontuacao {
        font-size: 8pt;
        color: #6b7280;
        font-style: italic;
        margin-left: auto;
    }

    /* === ALÍNEAS (Estilo académico) === */
    .alineas-container {
        margin-left: var(--spacing-lg);
        padding-left: var(--spacing-sm);
        border-left: 1px solid #e8e8e8;
    }

    .alinea {
        margin-bottom: var(--spacing-md);
        padding-bottom: var(--spacing-md);
        border-bottom: none;
    }
    
    .alinea:last-child {
        border-bottom: none;
        padding-bottom: 0;
        margin-bottom: 0;
    }

    .alinea-enunciado {
        flex-wrap: wrap;
        gap: var(--spacing-xs);
        align-items: baseline;
    }
    
    .alinea-letra {
        font-size: 10pt;
        font-weight: 600;
        min-width: auto;
        color: #1a1a1a;
    }

    .alinea-texto {
        font-size: 9.5pt;
        flex: 1;
        min-width: 0;
        color: #2c2c2c;
        line-height: 1.55;
    }
    
    .alinea-pontuacao {
        font-size: 7.5pt;
        color: #9ca3af;
        font-style: italic;
        margin-left: var(--spacing-sm);
    }

    /* === FÓRMULAS KATEX (Estilo académico) === */
    .katex-display {
        padding: var(--spacing-xs) 0;
        margin: var(--spacing-xs) 0;
        max-width: 100%;
        overflow-x: auto;
        overflow-y: hidden;
    }
    
    .katex {
        font-size: 0.9em !important;
        color: #1a1a1a;
    }

    /* === CONTAINER DE AÇÕES (fora do documento visual) === */
    .alinea-actions {
        display: flex;
        flex-direction: row;
        gap: var(--spacing-sm);
        margin-top: var(--spacing-md);
        padding-top: var(--spacing-sm);
        border-top: 1px dashed #d0d0d0;
        width: 100%;
        flex-wrap: wrap;
    }

    /* === BOTÕES (Compactos mas funcionais) === */
    .resolucao-container,
    .video-container {
        flex: 1;
        min-width: 130px;
    }

    .btn-toggle-resolucao,
    .btn-video {
        display: flex;
        align-items: center;
        justify-content: center;
        gap: var(--spacing-xs);
        width: 100%;
        padding: var(--spacing-sm) var(--spacing-md);
        font-size: 11px;
        font-weight: 500;
        border-radius: var(--radius-md);
        min-height: 40px;
        box-sizing: border-box;
    }
    
    .btn-toggle-resolucao {
        background: #f0fdf4;
        border: 1px solid #86efac;
        color: #166534;
    }
    
    .btn-toggle-resolucao:hover,
    .btn-toggle-resolucao:active {
        background: #dcfce7;
    }
    
    .btn-video {
        background: #eff6ff;
        border: 1px solid #93c5fd;
        color: #1e40af;
    }
    
    .btn-video:hover,
    .btn-video:active {
        background: #dbeafe;
    }

    /* === RESOLUÇÃO (Estilo académico) === */
    .resolucao-content {
        margin-top: var(--spacing-md);
        padding: var(--spacing-md);
        font-size: 9pt;
        border-radius: var(--radius-sm);
        background: #fefefe;
        border: 1px solid #e5e7eb;
        border-left: 3px solid #22c55e;
    }
    
    .resolucao-header {
        font-size: 9.5pt;
        font-weight: 600;
        margin-bottom: var(--spacing-xs);
        color: #166534;
    }
    
    .resolucao-texto {
        font-size: 9pt;
        line-height: 1.6;
        color: #374151;
    }

    /* === VÍDEO === */
    .video-player {
        margin-top: var(--spacing-md);
        width: 100%;
    }
    
    .video-wrapper {
        border-radius: var(--radius-sm);
        border: 1px solid #e5e7eb;
    }
    
    .btn-close-video {
        width: 100%;
        padding: var(--spacing-sm);
        margin-top: var(--spacing-sm);
        font-size: 12px;
        min-height: 36px;
        border-radius: var(--radius-sm);
        background: #f3f4f6;
        border: 1px solid #d1d5db;
        color: #374151;
    }

    /* === FOOTER DO DOCUMENTO (Estilo académico) === */
    .pdf-footer {
        position: relative;
        bottom: auto;
        left: auto;
        right: auto;
        margin-top: var(--spacing-xl);
        padding-top: var(--spacing-md);
        border-top: 1px solid #d0d0d0;
    }
    
    .pdf-footer-text {
        font-size: 7.5pt;
        color: #6b7280;
        text-align: center;
    }
    
    .pdf-footer-meta {
        font-size: 7pt;
        color: #9ca3af;
        text-align: center;
        margin-top: 2px;
    }

    /* === MODAL DE VÍDEO === */
    .video-modal-content {
        width: 100%;
        max-width: none;
        border-radius: 0;
        margin: 0;
    }
    
    .video-modal-close {
        top: 10px;
        right: 10px;
        background: rgba(0, 0, 0, 0.6);
        border-radius: 50%;
        width: var(--touch-target-min);
        height: var(--touch-target-min);
    }
    
    /* === GARANTIR NADA ULTRAPASSA === */
    * {
        max-width: 100%;
    }
}

/* =====================================================
   26. RESPONSIVO - MOBILE PEQUENO (≤ 400px)
   Mantém aparência de documento PDF
   ===================================================== */
@media (max-width: 400px) {
    /* Container continua com fundo cinza */
    .ficha-container {
        padding: var(--spacing-sm);
    }
    
    /* Documento PDF - margens menores mas mantém aparência */
    .pdf-document {
        padding: 12mm 8mm 10mm 8mm;
        font-size: 9.5pt;
        margin: 2px;
        width: calc(100% - 4px);
        /* Sombra mais subtil mas presente */
        box-shadow: 
            0 1px 4px rgba(0, 0, 0, 0.12),
            0 1px 2px rgba(0, 0, 0, 0.08);
    }
    
    .pdf-institution h3 {
        font-size: 10pt;
    }
    
    .pdf-year {
        font-size: 8pt;
    }
    
    .pdf-title h1 {
        font-size: 11pt;
        letter-spacing: 1px;
    }
    
    .pdf-title h2 {
        font-size: 9pt;
    }
    
    .exercicio-numero {
        font-size: 9.5pt;
    }
    
    .exercicio-enunciado-geral {
        font-size: 9pt;
    }
    
    .alinea-letra {
        font-size: 9pt;
    }
    
    .alinea-texto {
        font-size: 8.5pt;
    }
    
    .alinea-pontuacao {
        font-size: 7pt;
    }
    
    /* Botões lado a lado mais compactos */
    .alinea-actions {
        gap: var(--spacing-xs);
    }
    
    .btn-toggle-resolucao,
    .btn-video {
        font-size: 10px;
        padding: var(--spacing-xs) var(--spacing-sm);
        min-height: 36px;
    }
    
    .katex {
        font-size: 0.8em !important;
    }
    
    .resolucao-content {
        padding: var(--spacing-sm);
        font-size: 8.5pt;
    }
    
    .resolucao-header {
        font-size: 9pt;
    }
    
    .resolucao-texto {
        font-size: 8.5pt;
    }
    
    .pdf-footer-text {
        font-size: 7pt;
    }
    
    .pdf-footer-meta {
        font-size: 6.5pt;
    }
}

/* =====================================================
   27. PREFERÊNCIAS DO USUÁRIO
   ===================================================== */

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* High Contrast */
@media (prefers-contrast: high) {
    :root {
        --ficha-border: #000000;
        --btn-resolucao-border: #0056b3;
        --btn-video-border: #d97706;
    }
    
    .btn-toggle-resolucao,
    .btn-video {
        border-width: 3px;
    }
}

/* =====================================================
   28. ESTADOS DE LOADING
   ===================================================== */
.loading-skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
    border-radius: var(--radius-sm);
}

@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* =====================================================
   29. UTILIDADES
   ===================================================== */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.no-scroll {
    overflow: hidden;
}

/* =====================================================
   30. SISTEMA DE MODAIS
   ===================================================== */

/* Overlay do modal */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(4px);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 1rem;
    overflow-y: auto;
}

.modal-overlay.active {
    display: flex;
}

/* Container do modal */
.modal {
    background: #ffffff;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    animation: modalSlideIn 0.3s ease-out;
}

.modal-large {
    max-width: 900px;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-20px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Header do modal */
.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid #e5e7eb;
    background: #f9fafb;
}

.modal-header h3 {
    margin: 0;
    font-size: 1.125rem;
    font-weight: 600;
    color: #1f2937;
}

/* Botão fechar */
.modal-close {
    background: none;
    border: none;
    font-size: 1.75rem;
    line-height: 1;
    color: #6b7280;
    cursor: pointer;
    padding: 0.25rem 0.5rem;
    margin: -0.25rem -0.5rem -0.25rem 0;
    transition: color 0.2s, transform 0.2s;
    border-radius: 4px;
}

.modal-close:hover {
    color: #1f2937;
    transform: scale(1.1);
}

.modal-close:focus {
    outline: 2px solid #0ea5e9;
    outline-offset: 2px;
}

/* Body do modal */
.modal-body {
    padding: 1.5rem;
    overflow-y: auto;
    flex: 1;
    line-height: 1.6;
}

.modal-body p {
    margin: 0 0 1rem 0;
}

.modal-body p:last-child {
    margin-bottom: 0;
}

/* Iframes de vídeo nos modais */
.modal-body iframe {
    width: 100%;
    height: 450px;
    border-radius: 8px;
    border: none;
}

/* =====================================================
   31. BOTÕES DE AÇÃO (NÃO IMPRIMEM)
   ===================================================== */

.sub-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.75rem;
    flex-wrap: wrap;
}

.btn-action {
    background: #e0f2fe;
    border: 2px solid #0ea5e9;
    color: #0369a1;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.875rem;
    font-weight: 500;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.btn-action:hover {
    background: #bae6fd;
    border-color: #0284c7;
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(14, 165, 233, 0.2);
}

.btn-action:active {
    transform: translateY(0);
}

.btn-video {
    background: #fef3c7;
    border-color: #f59e0b;
    color: #92400e;
}

.btn-video:hover {
    background: #fde68a;
    border-color: #d97706;
    box-shadow: 0 2px 8px rgba(245, 158, 11, 0.2);
}

/* =====================================================
   32. ESPAÇO PARA RESPOSTA (SÓ NA IMPRESSÃO)
   ===================================================== */

.answer-space {
    display: none;
}

@media print {
    .answer-space {
        display: block;
        min-height: 80px;
        border-bottom: 1px solid #cccccc;
        margin-top: 0.5rem;
        margin-bottom: 1.5rem;
    }
}

/* =====================================================
   33. HEADER DA PÁGINA (NÃO IMPRIME)
   ===================================================== */

.header {
    background: #ffffff;
    border-bottom: 1px solid #e5e7eb;
    padding: 1rem 0;
    margin-bottom: 2rem;
}

.header-left,
.header-right {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.header-left {
    flex: 1;
}

.header-title h1 {
    margin: 0;
    font-size: 1.25rem;
    font-weight: 600;
    color: #1f2937;
}

.header-title small {
    color: #6b7280;
    font-size: 0.875rem;
}

.btn-icon {
    width: 2.5rem;
    height: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 6px;
    text-decoration: none;
    font-size: 1.5rem;
    color: #0ea5e9;
    transition: background 0.2s;
}

.btn-icon:hover {
    background: #e0f2fe;
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.btn-back {
    color: #0ea5e9;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

.btn-back:hover {
    color: #0284c7;
}

.header-actions,
.header-right {
    display: flex;
    gap: 0.75rem;
}

.btn {
    padding: 0.5rem 1rem;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.2s;
    display: inline-block;
    cursor: pointer;
    border: 2px solid transparent;
    background: #f3f4f6;
    color: #374151;
}

.btn:hover {
    background: #e5e7eb;
}

.btn-outline {
    background: #ffffff;
    border-color: #0ea5e9;
    color: #0ea5e9;
}

.btn-outline:hover {
    background: #e0f2fe;
}

.btn-primary {
    background: #0ea5e9;
    color: #ffffff;
    border-color: #0ea5e9;
}

.btn-primary:hover {
    background: #0284c7;
    border-color: #0284c7;
}

/* =====================================================
   33.1 CAMPOS DO ESTUDANTE (SÓ IMPRESSÃO)
   ===================================================== */

.student-fields {
    display: none;
    margin-top: 1.5rem;
    padding: 1rem;
    border: 1px solid #cccccc;
    border-radius: 4px;
    gap: 1rem;
    font-size: 0.875rem;
}

.student-fields span {
    display: inline-block;
}

@media print {
    .student-fields {
        display: flex;
        flex-wrap: wrap;
    }
}

/* Accent para o footer */
.accent {
    color: #0ea5e9;
}

/* =====================================================
   34. ESTILO GERAL DO BODY
   ===================================================== */

.bg-muted {
    background: #f5f5f5;
    min-height: 100vh;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

/* =====================================================
   35. ESTRUTURA DOS EXERCÍCIOS
   ===================================================== */

.exercise {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    page-break-inside: avoid;
}

.exercise-number {
    font-weight: 700;
    font-size: 14pt;
    color: #1f2937;
    min-width: 2rem;
    flex-shrink: 0;
}

.exercise-body {
    flex: 1;
}

.exercise-text {
    margin: 0 0 1rem 0;
    line-height: 1.6;
}

.exercise-points {
    color: #6b7280;
    font-size: 0.875rem;
    font-style: italic;
    margin-left: 0.5rem;
}

/* Alíneas */
.sub-question {
    margin-bottom: 1.5rem;
    page-break-inside: avoid;
}

.sub-question-content {
    display: flex;
    gap: 0.5rem;
    align-items: flex-start;
}

.sub-letter {
    font-weight: 600;
    color: #374151;
    min-width: 2rem;
    flex-shrink: 0;
}

.sub-question-content p {
    margin: 0;
    flex: 1;
    line-height: 1.6;
}

.sub-points {
    color: #6b7280;
    font-size: 0.875rem;
    font-style: italic;
    margin-left: 0.5rem;
}

/* Conteúdo LaTeX */
.latex-content {
    line-height: 1.8;
}

/* =====================================================
   36. RESPONSIVIDADE MOBILE
   ===================================================== */

@media (max-width: 768px) {
    .modal {
        max-width: 95%;
        width: 95%;
    }
    
    .modal-body iframe {
        height: 250px;
    }
    
    .header-content {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .sub-actions {
        flex-direction: column;
        width: 100%;
    }
    
    .btn-action {
        width: 100%;
        justify-content: center;
    }
}