/* =================================================================
   TASKS PROFESSIONAL STYLES - StudyHub
   Diseño profesional avanzado para la gestión de tareas con
   características modernas y experiencia de usuario optimizada
================================================================= */

/* Variables específicas para tareas */
:root {
    --tasks-gradient-bg: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --tasks-card-shadow: 0 8px 32px rgba(0, 0, 0, 0.12);
    --tasks-card-hover-shadow: 0 16px 48px rgba(0, 0, 0, 0.2);
    --tasks-header-bg: rgba(255, 255, 255, 0.95);
    --tasks-border: rgba(102, 126, 234, 0.2);
    --tasks-accent: #667eea;
    
    /* Colores de prioridad */
    --priority-high-color: #e74c3c;
    --priority-high-bg: rgba(231, 76, 60, 0.1);
    --priority-medium-color: #f39c12;
    --priority-medium-bg: rgba(243, 156, 18, 0.1);
    --priority-low-color: #27ae60;
    --priority-low-bg: rgba(39, 174, 96, 0.1);
    
    /* Estados de tareas */
    --task-pending-color: #3498db;
    --task-pending-bg: rgba(52, 152, 219, 0.1);
    --task-progress-color: #9b59b6;
    --task-progress-bg: rgba(155, 89, 182, 0.1);
    --task-completed-color: #2ecc71;
    --task-completed-bg: rgba(46, 204, 113, 0.1);
}

/* Header profesional de tareas */
.tasks-header {
    background: var(--tasks-header-bg);
    padding: 25px 30px;
    border-radius: var(--border-radius-lg);
    margin-bottom: 30px;
    border: 1px solid var(--tasks-border);
    backdrop-filter: blur(10px);
    position: relative;
    overflow: hidden;
}

.tasks-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--tasks-gradient-bg);
    z-index: 1;
}

.tasks-header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

/* Controles de sección */
.section-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    gap: 20px;
}

.section-controls .btn {
    flex-shrink: 0;
}

/* Contenedor de tareas */
.tasks-container {
    background: var(--bg-primary);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--tasks-card-shadow);
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.tasks-title {
    display: flex;
    align-items: center;
    gap: 15px;
}

.tasks-title h2 {
    color: var(--text-primary);
    font-size: 1.75rem;
    font-weight: 700;
    margin: 0;
}

.tasks-title i {
    font-size: 1.5rem;
    color: var(--tasks-accent);
}

.tasks-stats {
    display: flex;
    gap: 20px;
    align-items: center;
}

.task-stat-pill {
    background: var(--bg-secondary);
    padding: 8px 16px;
    border-radius: 20px;
    border: 1px solid var(--border-color);
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.task-stat-pill i {
    margin-right: 6px;
    color: var(--tasks-accent);
}

/* Filtros mejorados */
.tasks-filters {
    display: flex;
    gap: 12px;
    margin-bottom: 25px;
    flex-wrap: wrap;
    background: var(--bg-secondary);
    padding: 8px;
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--border-color);
}

.filter-btn {
    padding: 10px 18px;
    background: transparent;
    color: var(--text-secondary);
    border: none;
    border-radius: calc(var(--border-radius-lg) - 4px);
    cursor: pointer;
    transition: all var(--transition-medium);
    font-size: 0.875rem;
    font-weight: 500;
    position: relative;
    overflow: hidden;
    display: flex;
    align-items: center;
    gap: 8px;
}

.filter-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--tasks-gradient-bg);
    opacity: 0;
    transition: opacity var(--transition-medium);
    z-index: -1;
}

.filter-btn:hover {
    color: var(--text-primary);
    transform: translateY(-2px);
}

.filter-btn:hover::before {
    opacity: 0.1;
}

.filter-btn.active {
    background: var(--tasks-accent);
    color: white;
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
    transform: translateY(-2px);
}

.filter-btn.active::before {
    opacity: 1;
}

.filter-btn i {
    font-size: 0.875rem;
}

/* Lista de tareas mejorada */
.tasks-list {
    background: var(--bg-primary);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--tasks-card-shadow);
    overflow: hidden;
    border: 1px solid var(--border-color);
}

/* Tarjeta de tarea profesional */
.task-item {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    padding: 25px;
    border-bottom: 1px solid var(--border-light);
    transition: all var(--transition-medium);
    position: relative;
    overflow: hidden;
    background: var(--bg-primary);
}

.task-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 6px;
    background: var(--task-priority-color, var(--tasks-accent));
    transform: scaleY(0);
    transition: transform var(--transition-medium);
    z-index: 1;
}

.task-item:hover {
    background: var(--bg-secondary);
    transform: translateX(8px);
    box-shadow: var(--tasks-card-hover-shadow);
}

.task-item:hover::before {
    transform: scaleY(1);
}

.task-item:last-child {
    border-bottom: none;
}

/* Estados de tareas */
.task-item.pendiente {
    --task-priority-color: var(--task-pending-color);
}

.task-item.en_progreso {
    --task-priority-color: var(--task-progress-color);
    background: var(--task-progress-bg);
}

.task-item.terminado {
    --task-priority-color: var(--task-completed-color);
    background: var(--task-completed-bg);
    opacity: 0.8;
}

.task-item.terminado .task-title {
    text-decoration: line-through;
    opacity: 0.7;
}

/* Prioridades de tareas */
.task-item.priority-high {
    --task-priority-color: var(--priority-high-color);
}

.task-item.priority-medium {
    --task-priority-color: var(--priority-medium-color);
}

.task-item.priority-low {
    --task-priority-color: var(--priority-low-color);
}

.task-item.overdue {
    background: rgba(231, 76, 60, 0.05);
    border-left: 4px solid var(--priority-high-color);
}

/* Checkbox mejorado */
.task-checkbox {
    width: 24px;
    height: 24px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-medium);
    position: relative;
    flex-shrink: 0;
    background: var(--bg-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.task-checkbox::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0);
    width: 10px;
    height: 10px;
    background: var(--tasks-accent);
    border-radius: 2px;
    transition: transform var(--transition-fast);
}

.task-checkbox:hover {
    border-color: var(--tasks-accent);
    transform: scale(1.1);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.task-checkbox.completed {
    background: var(--tasks-accent);
    border-color: var(--tasks-accent);
    color: white;
}

.task-checkbox.completed::before {
    transform: translate(-50%, -50%) scale(1);
    background: white;
}

.task-checkbox.completed i {
    color: white;
    font-size: 0.75rem;
}

/* Detalles de la tarea */
.task-details {
    flex: 1;
    min-width: 0;
}

.task-title {
    font-weight: 700;
    color: var(--text-primary);
    margin: 0 0 8px 0;
    font-size: 1.125rem;
    line-height: 1.4;
    display: flex;
    align-items: center;
    gap: 10px;
}

.task-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin: 0 0 12px 0;
    line-height: 1.5;
    max-height: 60px;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    line-clamp: 2;
    -webkit-box-orient: vertical;
}

/* Metadatos de la tarea */
.task-meta {
    display: flex;
    gap: 15px;
    align-items: center;
    flex-wrap: wrap;
    margin-bottom: 10px;
}

.task-due-date {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.task-due-date i {
    color: var(--tasks-accent);
    font-size: 0.8rem;
}

.task-due-date.overdue {
    color: var(--priority-high-color);
    font-weight: 600;
}

.task-due-date.today {
    color: var(--priority-medium-color);
    font-weight: 600;
}

.task-due-date.tomorrow {
    color: var(--task-pending-color);
    font-weight: 600;
}

.task-subject {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8rem;
    padding: 4px 10px;
    background: var(--bg-tertiary);
    border-radius: 12px;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.task-subject i {
    color: var(--tasks-accent);
    font-size: 0.75rem;
}

.task-priority {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8rem;
    padding: 4px 10px;
    border-radius: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.task-priority.high {
    background: var(--priority-high-bg);
    color: var(--priority-high-color);
    border: 1px solid rgba(231, 76, 60, 0.3);
}

.task-priority.medium {
    background: var(--priority-medium-bg);
    color: var(--priority-medium-color);
    border: 1px solid rgba(243, 156, 18, 0.3);
}

.task-priority.low {
    background: var(--priority-low-bg);
    color: var(--priority-low-color);
    border: 1px solid rgba(39, 174, 96, 0.3);
}

/* Indicador de estado */
.task-status {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8rem;
    padding: 4px 10px;
    border-radius: 12px;
    font-weight: 600;
}

.task-status.pendiente {
    background: var(--task-pending-bg);
    color: var(--task-pending-color);
    border: 1px solid rgba(52, 152, 219, 0.3);
}

.task-status.en_progreso {
    background: var(--task-progress-bg);
    color: var(--task-progress-color);
    border: 1px solid rgba(155, 89, 182, 0.3);
}

.task-status.terminado {
    background: var(--task-completed-bg);
    color: var(--task-completed-color);
    border: 1px solid rgba(46, 204, 113, 0.3);
}

/* Acciones de la tarea */
.task-actions {
    display: flex;
    gap: 8px;
    align-items: flex-start;
    flex-shrink: 0;
}

.btn-icon {
    width: 36px;
    height: 36px;
    border: 1px solid var(--border-color);
    background: var(--bg-secondary);
    color: var(--text-secondary);
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.875rem;
}

.btn-icon:hover {
    background: var(--tasks-accent);
    color: white;
    border-color: var(--tasks-accent);
    transform: translateY(-2px) scale(1.05);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.btn-icon.btn-danger:hover {
    background: var(--priority-high-color);
    border-color: var(--priority-high-color);
    box-shadow: 0 4px 12px rgba(231, 76, 60, 0.3);
}

/* Estado vacío mejorado */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-secondary);
}

.empty-state i {
    font-size: 4rem;
    color: var(--tasks-accent);
    margin-bottom: 25px;
    opacity: 0.7;
}

.empty-state h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.empty-state p {
    font-size: 1rem;
    margin-bottom: 25px;
    max-width: 400px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.5;
}

.empty-state .btn {
    background: var(--tasks-gradient-bg);
    border: none;
    color: white;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    font-weight: 600;
    transition: all var(--transition-medium);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.empty-state .btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(102, 126, 234, 0.4);
}

/* Animaciones de entrada */
.task-item {
    animation: fadeInUp 0.6s ease-out;
    animation-fill-mode: both;
}

.task-item:nth-child(1) { animation-delay: 0.1s; }
.task-item:nth-child(2) { animation-delay: 0.2s; }
.task-item:nth-child(3) { animation-delay: 0.3s; }
.task-item:nth-child(4) { animation-delay: 0.4s; }
.task-item:nth-child(5) { animation-delay: 0.5s; }
.task-item:nth-child(6) { animation-delay: 0.6s; }

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Vista de tarjetas (alternativa) */
.tasks-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 20px;
    padding: 0;
}

.task-card {
    background: var(--bg-primary);
    border-radius: var(--border-radius-lg);
    padding: 25px;
    box-shadow: var(--tasks-card-shadow);
    border: 1px solid var(--border-color);
    transition: all var(--transition-medium);
    position: relative;
    overflow: hidden;
}

.task-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 6px;
    background: var(--task-priority-color, var(--tasks-accent));
    z-index: 1;
}

.task-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--tasks-card-hover-shadow);
}

.task-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 15px;
}

.task-card-body {
    margin-bottom: 20px;
}

.task-card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 20px;
    padding-top: 15px;
    border-top: 1px solid var(--border-light);
}

/* Toggle de vista */
.view-toggle {
    display: flex;
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    padding: 4px;
    border: 1px solid var(--border-color);
    margin-left: auto;
}

.view-toggle-btn {
    padding: 8px 12px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.875rem;
    border-radius: calc(var(--border-radius) - 2px);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 6px;
}

.view-toggle-btn.active {
    background: var(--tasks-accent);
    color: white;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.view-toggle-btn:hover:not(.active) {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

/* Estados de carga */
.tasks-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 60px 20px;
    color: var(--text-secondary);
}

.tasks-loading i {
    font-size: 3rem;
    color: var(--tasks-accent);
    margin-bottom: 20px;
    animation: pulse 2s infinite;
}

.tasks-loading p {
    font-size: 1.1rem;
    font-weight: 500;
}

/* =================================================================
   RESPONSIVE DESIGN PROFESIONAL
================================================================= */

@media (max-width: 1024px) {
    .tasks-grid {
        grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
        gap: 15px;
    }
    
    .tasks-header-content {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .tasks-stats {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 768px) {
    .tasks-grid {
        grid-template-columns: 1fr;
        gap: 15px;
    }
    
    .tasks-header {
        padding: 20px;
    }
    
    .tasks-filters {
        gap: 8px;
        padding: 6px;
    }
    
    .filter-btn {
        padding: 8px 14px;
        font-size: 0.8rem;
    }
    
    .task-item {
        padding: 20px;
        gap: 15px;
        flex-direction: column;
        align-items: flex-start;
    }
    
    .task-meta {
        flex-direction: column;
        gap: 8px;
        align-items: flex-start;
    }
    
    .task-actions {
        width: 100%;
        justify-content: flex-end;
    }
}

@media (max-width: 480px) {
    .tasks-header {
        padding: 15px;
    }
    
    .tasks-title h2 {
        font-size: 1.5rem;
    }
    
    .task-item {
        padding: 15px;
    }
    
    .task-title {
        font-size: 1rem;
    }
    
    .task-description {
        font-size: 0.85rem;
    }
    
    .task-meta {
        gap: 6px;
    }
    
    .task-due-date,
    .task-subject,
    .task-priority,
    .task-status {
        font-size: 0.75rem;
        padding: 3px 8px;
    }
}

/* =================================================================
   MODO OSCURO
================================================================= */

[data-theme="dark"] {
    --tasks-header-bg: rgba(45, 55, 72, 0.95);
    --tasks-border: rgba(102, 126, 234, 0.3);
    
    --priority-high-bg: rgba(231, 76, 60, 0.15);
    --priority-medium-bg: rgba(243, 156, 18, 0.15);
    --priority-low-bg: rgba(39, 174, 96, 0.15);
    
    --task-pending-bg: rgba(52, 152, 219, 0.15);
    --task-progress-bg: rgba(155, 89, 182, 0.15);
    --task-completed-bg: rgba(46, 204, 113, 0.15);
}

[data-theme="dark"] .task-item {
    background: var(--bg-secondary);
}

[data-theme="dark"] .task-item:hover {
    background: var(--bg-tertiary);
}

[data-theme="dark"] .task-checkbox {
    background: var(--bg-secondary);
    border-color: var(--border-color);
}

[data-theme="dark"] .empty-state i {
    opacity: 0.5;
}

/* =================================================================
   ESTILOS PARA MODAL DE TAREAS
================================================================= */

.modal-title-section {
    display: flex;
    align-items: center;
    gap: 10px;
}

.modal-title-section i {
    color: var(--tasks-accent);
    font-size: 1.25rem;
}

.form-group label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.form-group label i {
    color: var(--tasks-accent);
    font-size: 0.875rem;
    width: 16px;
}

.form-group input,
.form-group textarea,
.form-group select {
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 12px 16px;
    font-size: 0.9rem;
    transition: all var(--transition-medium);
    background: var(--bg-primary);
    color: var(--text-primary);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    border-color: var(--tasks-accent);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
    outline: none;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-secondary);
    opacity: 0.7;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

@media (max-width: 768px) {
    .form-row {
        grid-template-columns: 1fr;
        gap: 15px;
    }
}

/* Mejoras al botón del modal */
.modal-footer .btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    font-weight: 600;
}

.modal-footer .btn i {
    font-size: 0.875rem;
}