/* ============================================
   Daily Task Tracker - Styles
   A modern, responsive dark theme CSS
   ============================================ */

/* CSS Custom Properties (Variables) */
:root {
    /* Dark Theme Colors */
    --bg-primary: #0f0f1a;
    --bg-secondary: #1a1a2e;
    --bg-tertiary: #252542;
    --bg-card: #1e1e35;
    
    /* Text Colors */
    --text-primary: #ffffff;
    --text-secondary: #a0a0b8;
    --text-muted: #6c6c8a;
    
    /* Accent Colors */
    --accent-primary: #6366f1;
    --accent-primary-hover: #818cf8;
    --accent-secondary: #8b5cf6;
    --accent-success: #10b981;
    --accent-warning: #f59e0b;
    --accent-danger: #ef4444;
    
    /* Priority Colors */
    --priority-low: #10b981;
    --priority-medium: #f59e0b;
    --priority-high: #ef4444;
    
    /* Category Colors */
    --category-personal: #8b5cf6;
    --category-work: #3b82f6;
    --category-study: #06b6d4;
    --category-health: #10b981;
    --category-other: #6b7280;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3), 0 2px 4px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.4), 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.5), 0 10px 10px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);
    
    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.2s ease;
    --transition-slow: 0.3s ease;
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;
    
    /* Font Sizes */
    --font-xs: 0.75rem;
    --font-sm: 0.875rem;
    --font-md: 1rem;
    --font-lg: 1.125rem;
    --font-xl: 1.25rem;
    --font-2xl: 1.5rem;
    --font-3xl: 2rem;
}

/* Reset & Base Styles */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

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

/* Screen Reader Only */
.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;
}

/* App Container */
.app-container {
    max-width: 900px;
    margin: 0 auto;
    padding: var(--spacing-md);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ============================================
   Header Styles
   ============================================ */
.header {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #1a1a2e 100%);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(6, 182, 212, 0.2);
    position: relative;
    overflow: hidden;
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, #06b6d4, #3b82f6, #8b5cf6, #ec4899);
}

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

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-2xl);
    font-weight: 700;
    color: var(--text-primary);
}

.logo-icon {
    font-size: var(--font-3xl);
    animation: bounce 2s ease infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

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

/* ============================================
   Button Styles
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-md);
    font-weight: 500;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    outline: none;
}

.btn:focus-visible {
    box-shadow: 0 0 0 3px var(--accent-primary);
}

.btn-primary {
    background: linear-gradient(135deg, #06b6d4 0%, #3b82f6 50%, #8b5cf6 100%);
    color: white;
    box-shadow: var(--shadow-md);
    background-size: 200% 200%;
    animation: gradientShift 3s ease infinite;
}

@keyframes gradientShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(6, 182, 212, 0.4);
}

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

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.btn-secondary:hover {
    background: var(--bg-card);
    border-color: var(--accent-primary);
}

.btn-icon {
    width: 44px;
    height: 44px;
    padding: 0;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    font-size: var(--font-xl);
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.btn-icon:hover {
    background: var(--bg-card);
    transform: scale(1.05);
    box-shadow: var(--shadow-md);
}

.btn-add-task {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: var(--font-lg);
}

.btn-add-task .btn-icon {
    font-size: var(--font-2xl);
    font-weight: 300;
}

.btn-close {
    font-size: var(--font-2xl);
    width: 36px;
    height: 36px;
}

.btn-install {
    background: linear-gradient(135deg, #10b981 0%, #06b6d4 100%);
    color: white;
    font-size: var(--font-sm);
    padding: var(--spacing-xs) var(--spacing-sm);
    animation: pulse-install 2s ease infinite;
}

@keyframes pulse-install {
    0%, 100% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.4); }
    50% { box-shadow: 0 0 0 10px rgba(16, 185, 129, 0); }
}

.btn-install:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(16, 185, 129, 0.4);
}

.btn-sm {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--font-sm);
}

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

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

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

.btn-success:hover {
    background: #059669;
}

/* ============================================
   Stats Section
   ============================================ */
.stats-section {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.stat-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
}

.stat-card:nth-child(1)::before {
    background: linear-gradient(90deg, #3b82f6, #60a5fa);
}

.stat-card:nth-child(2)::before {
    background: linear-gradient(90deg, #10b981, #34d399);
}

.stat-card:nth-child(3)::before {
    background: linear-gradient(90deg, #f59e0b, #fbbf24);
}

.stat-card:nth-child(4)::before {
    background: linear-gradient(90deg, #ef4444, #f87171);
}

.stat-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.stat-card:nth-child(1):hover {
    box-shadow: 0 8px 20px rgba(59, 130, 246, 0.3);
}

.stat-card:nth-child(2):hover {
    box-shadow: 0 8px 20px rgba(16, 185, 129, 0.3);
}

.stat-card:nth-child(3):hover {
    box-shadow: 0 8px 20px rgba(245, 158, 11, 0.3);
}

.stat-card:nth-child(4):hover {
    box-shadow: 0 8px 20px rgba(239, 68, 68, 0.3);
}

.stat-number {
    display: block;
    font-size: var(--font-2xl);
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.stat-card:nth-child(1) .stat-number {
    color: #3b82f6;
}

.stat-card:nth-child(2) .stat-number {
    color: #10b981;
}

.stat-card:nth-child(3) .stat-number {
    color: #f59e0b;
}

.stat-card:nth-child(4) .stat-number {
    color: #ef4444;
}

.stat-label {
    font-size: var(--font-sm);
    color: var(--text-secondary);
}

/* ============================================
   Add Task Section
   ============================================ */
.add-task-section {
    margin-bottom: var(--spacing-lg);
}

/* ============================================
   Modal Styles
   ============================================ */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.modal.active {
    opacity: 1;
    visibility: visible;
}

.modal-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
}

.modal-content {
    position: relative;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-xl);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transform: scale(0.9) translateY(20px);
    transition: transform var(--transition-normal);
}

.modal.active .modal-content {
    transform: scale(1) translateY(0);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.modal-header h2 {
    font-size: var(--font-xl);
    font-weight: 600;
}

/* ============================================
   Form Styles
   ============================================ */
.task-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

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

.form-group label {
    font-size: var(--font-sm);
    font-weight: 500;
    color: var(--text-secondary);
}

.form-group input,
.form-group textarea,
.form-group select {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-md);
    background: var(--bg-tertiary);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    transition: all var(--transition-fast);
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

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

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

.form-group select {
    cursor: pointer;
}

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

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* ============================================
   Filter Section
   ============================================ */
.filter-section {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.filter-tabs {
    display: flex;
    gap: var(--spacing-xs);
    background: var(--bg-secondary);
    padding: var(--spacing-xs);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

.filter-tab {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-sm);
    font-weight: 500;
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.filter-tab.active {
    background: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(6, 182, 212, 0.4);
}

.sort-select {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-sm);
    background: var(--bg-secondary);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.sort-select:hover {
    border-color: var(--accent-primary);
}

.sort-select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

/* ============================================
   Tasks Section
   ============================================ */
.tasks-section {
    flex: 1;
    margin-bottom: var(--spacing-lg);
}

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

/* Empty State */
.empty-state {
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-2xl);
    text-align: center;
    color: var(--text-muted);
}

.empty-state.visible {
    display: flex;
}

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

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

/* ============================================
   Task Card Styles
   ============================================ */
.task-card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-md);
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: all var(--transition-normal);
    animation: slideIn 0.3s ease;
}

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

.task-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg), 0 0 20px rgba(6, 182, 212, 0.15);
    border-color: rgba(6, 182, 212, 0.3);
}

.task-card.completed {
    opacity: 0.7;
    background: var(--bg-tertiary);
}

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

.task-card.overdue {
    border-left: 4px solid var(--accent-danger);
}

.task-card.due-soon {
    border-left: 4px solid var(--accent-warning);
}

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

.task-info {
    flex: 1;
    min-width: 0;
}

.task-title-row {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
}

.task-checkbox {
    appearance: none;
    width: 22px;
    height: 22px;
    border: 2px solid var(--text-muted);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    flex-shrink: 0;
    position: relative;
}

.task-checkbox:hover {
    border-color: var(--accent-primary);
}

.task-checkbox:checked {
    background: var(--accent-success);
    border-color: var(--accent-success);
}

.task-checkbox:checked::after {
    content: '✓';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-size: 14px;
    font-weight: bold;
}

.task-title {
    font-size: var(--font-lg);
    font-weight: 600;
    color: var(--text-primary);
    word-break: break-word;
}

.task-description {
    font-size: var(--font-sm);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    word-break: break-word;
}

.task-meta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    font-size: var(--font-xs);
}

.task-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 2px 8px;
    border-radius: var(--radius-full);
    font-weight: 500;
}

.badge-priority {
    background: rgba(255, 255, 255, 0.1);
}

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

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

.badge-priority.high {
    color: var(--priority-high);
    animation: pulse 2s ease infinite;
}

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

.badge-category {
    background: rgba(255, 255, 255, 0.1);
}

.badge-category.personal { color: var(--category-personal); }
.badge-category.work { color: var(--category-work); }
.badge-category.study { color: var(--category-study); }
.badge-category.health { color: var(--category-health); }
.badge-category.other { color: var(--category-other); }

.badge-time {
    color: var(--text-muted);
    background: rgba(255, 255, 255, 0.05);
}

.badge-time.overdue {
    color: var(--accent-danger);
    background: rgba(239, 68, 68, 0.15);
}

.badge-time.due-soon {
    color: var(--accent-warning);
    background: rgba(245, 158, 11, 0.15);
}

.task-actions {
    display: flex;
    gap: var(--spacing-xs);
    flex-shrink: 0;
}

.task-action-btn {
    width: 32px;
    height: 32px;
    padding: 0;
    font-size: var(--font-md);
    background: var(--bg-tertiary);
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.task-action-btn:hover {
    transform: scale(1.1);
}

.task-action-btn.edit:hover {
    background: var(--accent-primary);
    color: white;
}

.task-action-btn.delete:hover {
    background: var(--accent-danger);
    color: white;
}

.task-action-btn.snooze:hover {
    background: var(--accent-warning);
    color: white;
}

/* ============================================
   History Section
   ============================================ */
.history-section {
    margin-bottom: var(--spacing-lg);
}

.history-details {
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    border: 1px solid rgba(255, 255, 255, 0.05);
    overflow: hidden;
}

.history-summary {
    padding: var(--spacing-md);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-weight: 500;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
    list-style: none;
}

.history-summary::-webkit-details-marker {
    display: none;
}

.history-summary::after {
    content: '▶';
    margin-left: auto;
    font-size: var(--font-xs);
    transition: transform var(--transition-fast);
}

.history-details[open] .history-summary::after {
    transform: rotate(90deg);
}

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

.history-icon {
    font-size: var(--font-lg);
}

.history-count {
    color: var(--text-muted);
    font-weight: 400;
}

.history-container {
    padding: var(--spacing-md);
    padding-top: 0;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    max-height: 300px;
    overflow-y: auto;
}

.history-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm);
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
    font-size: var(--font-sm);
}

.history-item-title {
    color: var(--text-secondary);
    text-decoration: line-through;
}

.history-item-date {
    color: var(--text-muted);
    font-size: var(--font-xs);
}

/* ============================================
   Footer Styles
   ============================================ */
.footer {
    text-align: center;
    padding: var(--spacing-lg);
    color: var(--text-muted);
    font-size: var(--font-sm);
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-sm);
}

.footer-links a {
    color: var(--text-muted);
    transition: all var(--transition-normal);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xs);
    border-radius: var(--radius-sm);
}

.footer-links a:hover {
    color: var(--accent-primary);
    transform: translateY(-2px);
}

/* ============================================
   Notification Badge
   ============================================ */
.notification-badge {
    position: relative;
}

.notification-badge::after {
    content: '';
    position: absolute;
    top: -2px;
    right: -2px;
    width: 10px;
    height: 10px;
    background: var(--accent-danger);
    border-radius: 50%;
    animation: pulse 1.5s ease infinite;
}

.notification-badge.enabled::after {
    background: linear-gradient(135deg, #10b981, #06b6d4);
}

/* ============================================
   Toast Notification
   ============================================ */
.toast {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-xl);
    border: 1px solid rgba(255, 255, 255, 0.1);
    z-index: 2000;
    transform: translateX(120%);
    transition: transform var(--transition-slow);
}

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

.toast.success {
    border-left: 4px solid var(--accent-success);
}

.toast.error {
    border-left: 4px solid var(--accent-danger);
}

.toast.warning {
    border-left: 4px solid var(--accent-warning);
}

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

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

::-webkit-scrollbar-thumb {
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
}

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

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
    .app-container {
        padding: var(--spacing-sm);
    }
    
    .header {
        padding: var(--spacing-md);
    }
    
    .logo {
        font-size: var(--font-xl);
    }
    
    .logo-icon {
        font-size: var(--font-2xl);
    }
    
    .stats-section {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .stat-card {
        padding: var(--spacing-sm);
    }
    
    .stat-number {
        font-size: var(--font-xl);
    }
    
    .filter-section {
        flex-direction: column;
        align-items: stretch;
    }
    
    .filter-tabs {
        justify-content: center;
    }
    
    .filter-tab {
        padding: var(--spacing-xs) var(--spacing-sm);
        font-size: var(--font-xs);
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        padding: var(--spacing-md);
        margin: var(--spacing-md);
    }
    
    .task-header {
        flex-direction: column;
    }
    
    .task-actions {
        align-self: flex-end;
    }
    
    .toast {
        left: var(--spacing-md);
        right: var(--spacing-md);
        bottom: var(--spacing-md);
    }
}

@media (max-width: 480px) {
    .header-content {
        flex-direction: column;
        text-align: center;
    }
    
    .stats-section {
        grid-template-columns: 1fr 1fr;
        gap: var(--spacing-sm);
    }
    
    .stat-number {
        font-size: var(--font-lg);
    }
    
    .stat-label {
        font-size: var(--font-xs);
    }
    
    .task-meta {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* ============================================
   Animations
   ============================================ */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

.shake {
    animation: shake 0.3s ease;
}

/* Print Styles */
@media print {
    .header-actions,
    .add-task-section,
    .filter-section,
    .task-actions,
    .history-section,
    .footer {
        display: none;
    }
    
    .task-card {
        box-shadow: none;
        border: 1px solid #ccc;
        break-inside: avoid;
    }
}