/* ===== VARIABLES ===== */
:root {
    /* Colors */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --info: #3b82f6;
    
    /* Neutral Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #94a3b8;
    --border: #e2e8f0;
    --shadow: rgba(0, 0, 0, 0.1);
    
    /* Priority Colors */
    --priority-low: #10b981;
    --priority-medium: #f59e0b;
    --priority-high: #ef4444;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transitions */
    --transition: all 0.3s ease;
}

/* Dark Theme */
body.dark-theme {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-tertiary: #64748b;
    --border: #334155;
    --shadow: rgba(0, 0, 0, 0.3);
}

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

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

/* ===== HEADER ===== */
.header {
    background-color: var(--bg-primary);
    box-shadow: 0 1px 3px var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: var(--transition);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--primary);
}

.logo i {
    font-size: 1.75rem;
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

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

/* ===== CONTAINER ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ===== MAIN ===== */
.main {
    padding: var(--spacing-xl) 0;
}

/* ===== STATS GRID ===== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.stat-card {
    background-color: var(--bg-primary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: 0 1px 3px var(--shadow);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    transition: var(--transition);
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow);
}

.stat-icon {
    width: 50px;
    height: 50px;
    border-radius: var(--radius-md);
    background-color: rgba(99, 102, 241, 0.1);
    color: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.stat-icon-success {
    background-color: rgba(16, 185, 129, 0.1);
    color: var(--success);
}

.stat-icon-warning {
    background-color: rgba(245, 158, 11, 0.1);
    color: var(--warning);
}

.stat-info {
    flex: 1;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
}

.stat-value {
    font-size: 1.875rem;
    font-weight: 700;
    color: var(--text-primary);
}

/* ===== TASK FORM CARD ===== */
.task-form-card {
    background-color: var(--bg-primary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: 0 1px 3px var(--shadow);
    margin-bottom: var(--spacing-xl);
}

.task-form-card h2 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

/* ===== FORM ===== */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.form-input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-family: inherit;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    transition: var(--transition);
}

.form-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

textarea.form-input {
    resize: vertical;
    min-height: 80px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
    user-select: none;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

/* ===== BUTTONS ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-family: inherit;
}

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

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.btn-secondary {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background-color: var(--border);
}

.btn-icon {
    width: 40px;
    height: 40px;
    border: none;
    border-radius: var(--radius-md);
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    font-size: 1.125rem;
}

.btn-icon:hover {
    background-color: var(--border);
    transform: scale(1.05);
}

/* ===== FILTERS ===== */
.filters {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
}

.filter-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    background-color: var(--bg-primary);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    font-family: inherit;
    font-size: 0.875rem;
    font-weight: 500;
}

.filter-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
}

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

/* ===== TASKS CONTAINER ===== */
.tasks-container {
    background-color: var(--bg-primary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: 0 1px 3px var(--shadow);
    min-height: 400px;
}

.tasks-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

/* ===== TASK CARD ===== */
.task-card {
    background-color: var(--bg-secondary);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    transition: var(--transition);
    cursor: pointer;
}

.task-card:hover {
    border-color: var(--primary);
    transform: translateX(4px);
    box-shadow: 0 2px 8px var(--shadow);
}

.task-card.completed {
    opacity: 0.7;
}

.task-header {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.task-checkbox {
    width: 24px;
    height: 24px;
    cursor: pointer;
    margin-top: 2px;
}

.task-content {
    flex: 1;
}

.task-title-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.task-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
}

.task-card.completed .task-title {
    text-decoration: line-through;
    color: var(--text-tertiary);
}

.priority-badge {
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

.priority-low {
    background-color: rgba(16, 185, 129, 0.1);
    color: var(--priority-low);
}

.priority-medium {
    background-color: rgba(245, 158, 11, 0.1);
    color: var(--priority-medium);
}

.priority-high {
    background-color: rgba(239, 68, 68, 0.1);
    color: var(--priority-high);
}

.task-description {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.5;
}

.task-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.task-meta-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

.task-meta-item i {
    font-size: 1rem;
}

.task-actions {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.btn-small {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: 0.875rem;
}

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

.btn-danger:hover {
    background-color: #dc2626;
}

/* ===== EMPTY STATE ===== */
.empty-state {
    text-align: center;
    padding: var(--spacing-2xl);
    color: var(--text-tertiary);
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
    opacity: 0.5;
}

.empty-state h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

.empty-state p {
    font-size: 0.875rem;
}

/* ===== MODAL ===== */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
}

.modal.active {
    display: flex;
}

.modal-content {
    background-color: var(--bg-primary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    max-width: 500px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    animation: modalSlideIn 0.3s ease;
}

.modal-large {
    max-width: 700px;
}

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

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
}

.modal-header h3 {
    font-size: 1.5rem;
    color: var(--text-primary);
}

.btn-close {
    width: 32px;
    height: 32px;
    border: none;
    background-color: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

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

.modal-body {
    color: var(--text-primary);
}

.modal-actions {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.modal-actions .btn {
    flex: 1;
}

/* ===== LANGUAGE SELECTOR ===== */
.lang-options {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
}

.lang-option {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    background-color: var(--bg-secondary);
    cursor: pointer;
    transition: var(--transition);
    font-size: 1rem;
    font-family: inherit;
    color: var(--text-primary);
}

.lang-option:hover {
    border-color: var(--primary);
    background-color: rgba(99, 102, 241, 0.05);
}

.lang-option .flag {
    font-size: 1.5rem;
}

/* ===== NOTIFICATION PROMPT ===== */
.notification-prompt {
    text-align: center;
}

.notification-prompt i {
    color: var(--primary);
    margin-bottom: var(--spacing-lg);
}

.notification-prompt h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.notification-prompt p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

/* ===== TOAST ===== */
.toast {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    background-color: var(--success);
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    transform: translateX(400px);
    transition: transform 0.3s ease;
    z-index: 2000;
}

.toast.show {
    transform: translateX(0);
}

.toast i {
    font-size: 1.25rem;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
    .header-content {
        padding: var(--spacing-sm) 0;
    }
    
    .logo h1 {
        font-size: 1.25rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .task-form-card {
        padding: var(--spacing-lg);
    }
    
    .tasks-container {
        padding: var(--spacing-lg);
    }
    
    .filters {
        overflow-x: auto;
        flex-wrap: nowrap;
        padding-bottom: var(--spacing-sm);
    }
    
    .filter-btn {
        white-space: nowrap;
    }
    
    .task-title-row {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .task-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-sm);
    }
    
    .modal-content {
        margin: var(--spacing-md);
    }
    
    .toast {
        bottom: var(--spacing-md);
        right: var(--spacing-md);
        left: var(--spacing-md);
    }
}

/* ===== ANIMATIONS ===== */
.fade-in {
    animation: fadeIn 0.3s ease;
}

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

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
}

::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-tertiary);
}

/* ===== PRINT STYLES ===== */
@media print {
    .header-actions,
    .task-form-card,
    .filters,
    .task-actions,
    .toast {
        display: none !important;
    }
}