/* ===== VARIABLES CSS ===== */
:root {
    /* Colores principales */
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #06b6d4;
    
    /* Colores de fondo */
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #334155;
    --bg-overlay: rgba(0, 0, 0, 0.8);
    
    /* Colores de texto */
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    
    /* Bordes y sombras */
    --border-color: #475569;
    --border-light: #64748b;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    
    /* Espaciado */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Bordes redondeados */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transiciones */
    --transition-fast: 0.15s ease-in-out;
    --transition-normal: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;
}

/* ===== TEMA CLARO ===== */
.theme-light {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-card: #ffffff;
    --bg-overlay: rgba(0, 0, 0, 0.5);
    --text-primary: #1e293b;
    --text-secondary: #475569;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --border-light: #cbd5e1;
}

/* ===== RESET Y BASE ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

/* ===== LAYOUT PRINCIPAL ===== */
.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    width: 100%;
}

/* ===== HEADER ===== */
.app-header {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-md);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-lg);
    position: relative;
}

.header-left {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    justify-content: center;
    flex: 1;
}

/* Botón volver posicionado absolutamente */
.button-wrap {
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
}

/* Botón volver */
.button-wrap {
    position: relative;
    display: inline-block;
}

.button-wrap button {
    background: var(--primary-color);
    border: none;
    border-radius: var(--radius-lg);
    padding: var(--spacing-sm);
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    position: relative;
    z-index: 2;
}

.button-wrap button:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
}

.button-shadow {
    position: absolute;
    top: 4px;
    left: 0;
    right: 0;
    bottom: -4px;
    background: var(--primary-hover);
    border-radius: var(--radius-lg);
    z-index: 1;
    opacity: 0.3;
}

/* Título y subtítulo */
.app-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
}

.app-title svg {
    color: var(--primary-color);
}

.app-subtitle {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 400;
}

/* ===== CONTENIDO PRINCIPAL ===== */
.main-content {
    flex: 1;
    padding: var(--spacing-lg);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: calc(100vh - 120px);
}

.container {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--border-color);
    width: 100%;
    max-width: 800px;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
}

/* ===== DISPLAY PRINCIPAL ===== */
.main-display {
    margin-bottom: var(--spacing-xl);
}

.file-upload-area {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-2xl);
    text-align: center;
    cursor: pointer;
    transition: var(--transition-fast);
    background: var(--bg-secondary);
    position: relative;
    overflow: hidden;
}

.file-upload-area:hover {
    border-color: var(--primary-color);
    background: rgba(59, 130, 246, 0.05);
}

.file-upload-area.drag-over {
    border-color: var(--primary-color);
    background: rgba(59, 130, 246, 0.1);
    transform: scale(1.02);
}

.upload-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-md);
}

.upload-icon {
    font-size: 3rem;
    color: var(--primary-color);
}

.upload-text {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.upload-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.upload-subtitle {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* ===== ESTADÍSTICAS ===== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.stat-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    text-align: center;
    transition: var(--transition-fast);
}

.stat-card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    line-height: 1;
}

.stat-value.primary {
    color: var(--primary-color);
}

.stat-value.success {
    color: var(--success-color);
}

.stat-value.error {
    color: var(--error-color);
}

.stat-value.info {
    color: var(--info-color);
}

/* ===== BOTONES DE ACCIÓN ===== */
.action-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.btn-action {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-lg);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-fast);
    text-decoration: none;
    min-height: 56px;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--border-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-success {
    background: var(--success-color);
    color: white;
}

.btn-success:hover {
    background: #059669;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-info {
    background: var(--info-color);
    color: white;
}

.btn-info:hover {
    background: #0891b2;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-error {
    background: var(--error-color);
    color: white;
}

.btn-error:hover {
    background: #dc2626;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-action:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

/* ===== INDICADOR DE ESTADO ===== */
.status-indicator {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ===== MODAL ===== */
.content-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-overlay);
    z-index: 1000;
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px);
}

.content-modal.show {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
}

.modal-content {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--border-color);
    width: 100%;
    max-width: 900px;
    max-height: 90vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.modal-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--bg-secondary);
}

.modal-title-section {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.modal-title-section h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.modal-stats-display {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
}

.modal-timer-display {
    background: var(--primary-color);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    font-family: 'Courier New', monospace;
    font-size: 1.125rem;
    font-weight: 600;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    min-width: 80px;
    text-align: center;
}

.modal-word-count-display {
    background: var(--success-color);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    font-family: 'Courier New', monospace;
    font-size: 1.125rem;
    font-weight: 600;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    min-width: 80px;
    text-align: center;
}

.modal-error-count-display {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    color: var(--text-secondary);
    background: var(--bg-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-light);
}

.modal-accuracy-display {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    color: var(--text-secondary);
    background: var(--bg-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-light);
}

.error-count-label, .accuracy-label {
    font-weight: 600;
    color: var(--text-secondary);
}

#modal-error-count {
    font-weight: 700;
    color: var(--error-color);
}

#modal-accuracy {
    font-weight: 700;
    color: var(--success-color);
}

#modal-accuracy.warning {
    color: var(--warning-color);
}

#modal-accuracy.error {
    color: var(--error-color);
}

.timer-label, .word-count-label {
    font-size: 0.75rem;
    font-weight: 400;
    opacity: 0.8;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.close-modal {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-secondary);
    cursor: pointer;
    padding: var(--spacing-xs);
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

.close-modal:hover {
    background: var(--bg-primary);
    color: var(--text-primary);
}

/* ===== SELECTORES DE CURSO ===== */
.course-selector-section {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-secondary);
}

.selector-row {
    display: grid;
    grid-template-columns: 1fr 1fr auto;
    gap: var(--spacing-lg);
    align-items: end;
    margin-bottom: var(--spacing-md);
}

.selector-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.selector-group label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.course-select,
.student-select {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition-fast);
    cursor: pointer;
}

.course-select:focus,
.student-select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.course-select:hover,
.student-select:hover {
    border-color: var(--border-light);
}

.course-select:disabled,
.student-select:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.selector-actions {
    display: flex;
    gap: var(--spacing-sm);
}

.refresh-btn {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
}

.refresh-btn:hover {
    border-color: var(--primary-color);
    background: rgba(59, 130, 246, 0.1);
}

.add-course-btn {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    border: none;
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    color: white;
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    font-weight: 600;
    box-shadow: 0 2px 4px rgba(16, 185, 129, 0.2);
}

.add-course-btn:hover {
    background: linear-gradient(135deg, #059669 0%, #047857 100%);
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(16, 185, 129, 0.3);
}

/* ===== CONTROLES DE TIMER ===== */
.modal-timer-controls {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-secondary);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.timer-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-fast);
}

.timer-btn.start {
    background: var(--success-color);
    color: white;
}

.timer-btn.start:hover:not(:disabled) {
    background: #059669;
    transform: translateY(-1px);
}

.timer-btn.pause {
    background: var(--warning-color);
    color: white;
}

.timer-btn.pause:hover:not(:disabled) {
    background: #d97706;
    transform: translateY(-1px);
}

.timer-btn.reset {
    background: var(--error-color);
    color: white;
}

.timer-btn.reset:hover:not(:disabled) {
    background: #dc2626;
    transform: translateY(-1px);
}

.timer-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

.timer-info {
    margin-left: auto;
    font-size: 0.75rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.timer-info kbd {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.75rem;
    font-family: monospace;
}

/* ===== CUERPO DEL MODAL ===== */
.modal-body {
    padding: var(--spacing-lg);
    overflow-y: auto;
    flex: 1;
    max-height: 400px;
}

.text-content {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    font-size: 1rem;
}

/* Estilos para palabras seleccionadas y mal pronunciadas */
.text-content span.selected {
    background-color: var(--success-color) !important;
    color: white !important;
    border-radius: var(--radius-sm);
    padding: 2px 4px;
    transition: var(--transition-fast);
}

.text-content span.mispronounced {
    background-color: var(--error-color) !important;
    color: white !important;
    border-radius: var(--radius-sm);
    padding: 2px 4px;
    transition: var(--transition-fast);
}

.text-content span.selected.mispronounced {
    background-color: var(--error-color) !important;
    color: white !important;
}

/* ===== MODAL DE SESIONES ===== */
.sessions-summary {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.sessions-container {
    max-height: 400px;
    overflow-y: auto;
}

.session-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    transition: var(--transition-fast);
}

.session-card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
}

.session-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-md);
}

.session-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.session-date {
    color: var(--text-secondary);
    font-size: 0.75rem;
    margin-top: var(--spacing-xs);
}

.session-id-display {
    color: var(--primary-color);
    font-size: 0.7rem;
    font-family: 'Courier New', monospace;
    font-weight: 600;
    margin-top: var(--spacing-xs);
    opacity: 0.8;
}

.session-status {
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.session-status.completed {
    background: var(--success-color);
    color: white;
}

.session-status.pending {
    background: var(--warning-color);
    color: white;
}

.session-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.session-detail {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.session-detail-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 600;
}

.session-detail-value {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.session-actions {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.session-btn {
    padding: var(--spacing-xs) var(--spacing-sm);
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.session-btn.resume {
    background: var(--primary-color);
    color: white;
}

.session-btn.resume:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

.session-btn.view {
    background: var(--info-color);
    color: white;
}

.session-btn.view:hover {
    background: #0891b2;
    transform: translateY(-1px);
}

.session-btn.delete {
    background: var(--error-color);
    color: white;
}

.session-btn.delete:hover {
    background: #dc2626;
    transform: translateY(-1px);
}

.no-sessions {
    text-align: center;
    padding: var(--spacing-2xl);
    color: var(--text-secondary);
}

.no-sessions-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    opacity: 0.5;
}

.no-sessions h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.no-sessions p {
    font-size: 0.875rem;
    line-height: 1.5;
}

.text-content {
    line-height: 1.8;
    color: var(--text-primary);
    white-space: pre-wrap;
    word-wrap: break-word;
    max-height: 300px;
    overflow-y: auto;
}

.text-content.reading {
    background: var(--bg-secondary);
    border-color: var(--primary-color);
}

/* ===== PIE DEL MODAL ===== */
.modal-footer {
    padding: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: var(--spacing-md);
    justify-content: flex-end;
    background: var(--bg-secondary);
}

.btn-modal {
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.btn-modal:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* Estilos específicos para botones de evaluación */
.btn-modal.btn-primary {
    background: var(--primary-color);
    color: white;
    border: 1px solid var(--primary-color);
}

.btn-modal.btn-primary:hover:not(:disabled) {
    background: var(--primary-hover);
    border-color: var(--primary-hover);
}

.btn-modal.btn-primary:disabled {
    background: var(--text-muted);
    border-color: var(--text-muted);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

/* ===== RESPONSIVIDAD ===== */

/* Tablet (768px - 1023px) */
@media (max-width: 1023px) {
    .app-header {
        padding: var(--spacing-lg);
    }
    
    .header-content {
        flex-direction: column;
        align-items: center;
        gap: var(--spacing-md);
        justify-content: center;
    }
    
    .header-left {
        width: 100%;
        justify-content: center;
    }
    
    .button-wrap {
        position: absolute;
        left: 0;
        top: 0;
        transform: none;
    }
    
    .main-content {
        padding: var(--spacing-md);
    }
    
    .container {
        padding: var(--spacing-lg);
        margin: 0;
        border-radius: var(--radius-lg);
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-md);
    }
    
    .action-buttons {
        grid-template-columns: 1fr;
    }
    
    .btn-action {
        min-height: 64px;
        font-size: 1.125rem;
    }
    
    .modal-content {
        margin: var(--spacing-md);
        max-height: calc(100vh - 2rem);
    }
    
    .selector-row {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .modal-timer-controls {
        flex-direction: column;
        align-items: stretch;
        gap: var(--spacing-sm);
    }
    
    .timer-info {
        margin-left: 0;
        justify-content: center;
    }
}

/* Móvil (hasta 767px) */
@media (max-width: 767px) {
    html {
        font-size: 14px;
    }
    
    .app-header {
        padding: var(--spacing-md);
    }
    
    .header-content {
        gap: var(--spacing-sm);
        justify-content: center;
    }
    
    .header-left {
        flex-direction: column;
        align-items: center;
        gap: var(--spacing-md);
        justify-content: center;
    }
    
    .button-wrap {
        position: absolute;
        left: 0;
        top: 0;
        transform: none;
    }
    
    .app-title {
        font-size: 1.25rem;
    }
    
    .app-subtitle {
        font-size: 0.8rem;
    }
    
    .main-content {
        padding: var(--spacing-sm);
    }
    
    .container {
        padding: var(--spacing-md);
        border-radius: var(--radius-md);
    }
    
    .file-upload-area {
        padding: var(--spacing-xl);
    }
    
    .upload-icon {
        font-size: 2.5rem;
    }
    
    .upload-title {
        font-size: 1.125rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .stat-value {
        font-size: 1.75rem;
    }
    
    .action-buttons {
        gap: var(--spacing-sm);
    }
    
    .btn-action {
        min-height: 56px;
        font-size: 1rem;
        padding: var(--spacing-md);
    }
    
    .modal-content {
        margin: var(--spacing-sm);
        border-radius: var(--radius-lg);
    }
    
    .modal-header,
    .modal-body,
    .modal-footer {
        padding: var(--spacing-md);
    }
    
    .modal-footer {
        flex-direction: column;
    }
    
    .btn-modal {
        width: 100%;
        padding: var(--spacing-md);
    }
    
    .course-selector-section {
        padding: var(--spacing-md);
    }
    
    .selector-actions {
        flex-direction: column;
        gap: var(--spacing-xs);
    }
    
    .add-course-btn {
        width: 100%;
        justify-content: center;
    }
    
    .modal-timer-controls {
        padding: var(--spacing-md);
    }
    
    .text-content {
        padding: var(--spacing-md);
        font-size: 0.875rem;
        max-height: 250px;
    }
    
    .modal-stats-display {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .modal-timer-display,
    .modal-word-count-display,
    .modal-error-count-display,
    .modal-accuracy-display {
        min-width: 60px;
        font-size: 1rem;
    }
    
    .session-details {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    .session-actions {
        flex-direction: column;
    }
    
    .session-btn {
        justify-content: center;
    }
}

/* Móvil pequeño (hasta 480px) */
@media (max-width: 480px) {
    .app-header {
        padding: var(--spacing-sm);
    }
    
    .header-content {
        gap: var(--spacing-sm);
    }
    
    .button-wrap button {
        width: 40px;
        height: 40px;
    }
    
    .app-title {
        font-size: 1.125rem;
    }
    
    .main-content {
        padding: var(--spacing-xs);
    }
    
    .container {
        padding: var(--spacing-sm);
        border-radius: var(--radius-sm);
    }
    
    .file-upload-area {
        padding: var(--spacing-lg);
    }
    
    .upload-icon {
        font-size: 2rem;
    }
    
    .btn-action {
        min-height: 48px;
        font-size: 0.875rem;
        padding: var(--spacing-sm) var(--spacing-md);
    }
    
    .modal-content {
        margin: var(--spacing-xs);
        border-radius: var(--radius-md);
    }
    
    .modal-header,
    .modal-body,
    .modal-footer {
        padding: var(--spacing-sm);
    }
    
    .course-selector-section {
        padding: var(--spacing-sm);
    }
    
    .modal-timer-controls {
        padding: var(--spacing-sm);
    }
    
    .text-content {
        padding: var(--spacing-sm);
        font-size: 0.8rem;
        max-height: 200px;
    }
    
    .modal-stats-display {
        flex-direction: column;
        gap: var(--spacing-xs);
    }
    
    .modal-timer-display,
    .modal-word-count-display,
    .modal-error-count-display,
    .modal-accuracy-display {
        min-width: 50px;
        font-size: 0.9rem;
        padding: var(--spacing-xs) var(--spacing-sm);
    }
    
    .timer-label, .word-count-label {
        font-size: 0.7rem;
    }
    
    .session-header {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .session-details {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    .session-actions {
        flex-direction: column;
        gap: var(--spacing-xs);
    }
    
    .session-btn {
        justify-content: center;
        padding: var(--spacing-sm);
    }
}

/* ===== ANIMACIONES ===== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

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

.container {
    animation: fadeIn 0.5s ease-out;
}

.modal-content {
    animation: slideIn 0.3s ease-out;
}

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

/* ===== ESTADOS DE CARGA ===== */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid var(--primary-color);
    border-top: 2px solid transparent;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* ===== ACCESIBILIDAD ===== */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus visible para navegación por teclado */
button:focus-visible,
select:focus-visible,
input:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

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

.text-center {
    text-align: center;
}

.text-left {
    text-align: left;
}

.text-right {
    text-align: right;
}

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mb-5 { margin-bottom: var(--spacing-xl); }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }
.mt-5 { margin-top: var(--spacing-xl); }

/* ===== MODAL DE DETALLES DE SESIÓN ===== */
.session-details-content {
    padding: var(--spacing-md);
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.session-details-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.session-detail-item {
    background: var(--bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-light);
}

.session-detail-item h4 {
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.session-detail-item .value {
    color: var(--text-primary);
    font-size: 1.125rem;
    font-weight: 700;
}

.session-detail-item .value.success {
    color: var(--success-color);
}

.session-detail-item .value.error {
    color: var(--error-color);
}

.session-detail-item .value.warning {
    color: var(--warning-color);
}

.session-students-list {
    background: var(--bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-light);
    margin-top: var(--spacing-md);
}

.session-students-list h4 {
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.students-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.student-tag {
    background: var(--primary-color);
    color: white;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 500;
}

.session-status-badge {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.session-status-badge.completed {
    background: var(--success-color);
    color: white;
}

.session-status-badge.pending {
    background: var(--warning-color);
    color: white;
}

/* Estilos para el ID de sesión */
.session-detail-item .value.session-id {
    font-family: 'Courier New', monospace;
    font-size: 0.875rem;
    background: var(--bg-primary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-light);
    color: var(--primary-color);
    font-weight: 600;
    letter-spacing: 0.5px;
    word-break: break-all;
}

/* Responsive para el modal de detalles */
@media (max-width: 767px) {
    .session-details-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    .session-detail-item {
        padding: var(--spacing-sm);
    }
    
    .session-detail-item .value {
        font-size: 1rem;
    }
    
    .students-tags {
        gap: var(--spacing-xs);
    }
    
    .student-tag {
        font-size: 0.7rem;
        padding: var(--spacing-xs);
    }
}

/* ===== ANIMACIONES PARA NOTIFICACIONES ===== */
@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes slideOutRight {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(100%);
        opacity: 0;
    }
}

/* ===== ESTILOS DE NOTIFICACIONES ===== */
.notification-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-sm);
}

.notification-message {
    flex: 1;
}

.notification-close {
    background: none;
    border: none;
    color: white;
    font-size: 1.2rem;
    cursor: pointer;
    padding: 0;
    width: 20px;
    height: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: background-color 0.2s ease;
}

.notification-close:hover {
    background: rgba(255, 255, 255, 0.2);
}