/* ===== CSS VARIABLES ===== */
:root {
    /* Default Theme Colors */
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #f093fb;
    --success-color: #48bb78;
    --warning-color: #ed8936;
    --danger-color: #e53e3e;
    --info-color: #38b2ac;
    
    /* Background Colors */
    --bg-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --bg-secondary: rgba(255, 255, 255, 0.95);
    --bg-tertiary: rgba(255, 255, 255, 0.8);
    --bg-overlay: rgba(0, 0, 0, 0.5);
    
    /* Text Colors */
    --text-primary: #2d3748;
    --text-secondary: #4a5568;
    --text-muted: #718096;
    --text-light: #ffffff;
    
    /* Border Colors */
    --border-color: rgba(0, 0, 0, 0.1);
    --border-focus: var(--primary-color);
    
    /* Shadow */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.2);
    
    /* 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;
    
    /* Font Settings */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Z-index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1050;
    --z-modal-backdrop: 1040;
    --z-modal: 1060;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

/* ===== THEME VARIATIONS ===== */
[data-theme="dark"] {
    --bg-primary: linear-gradient(135deg, #1a202c 0%, #2d3748 100%);
    --bg-secondary: rgba(45, 55, 72, 0.95);
    --bg-tertiary: rgba(45, 55, 72, 0.8);
    --text-primary: #f7fafc;
    --text-secondary: #e2e8f0;
    --text-muted: #a0aec0;
    --border-color: rgba(255, 255, 255, 0.1);
}

[data-theme="light"] {
    --bg-primary: linear-gradient(135deg, #f7fafc 0%, #edf2f7 100%);
    --bg-secondary: rgba(255, 255, 255, 0.98);
    --bg-tertiary: rgba(255, 255, 255, 0.9);
    --primary-color: #4299e1;
    --secondary-color: #3182ce;
}

[data-theme="blue"] {
    --primary-color: #3182ce;
    --secondary-color: #2c5282;
    --bg-primary: linear-gradient(135deg, #3182ce 0%, #2c5282 100%);
}

[data-theme="green"] {
    --primary-color: #38a169;
    --secondary-color: #2f855a;
    --bg-primary: linear-gradient(135deg, #38a169 0%, #2f855a 100%);
}

[data-theme="purple"] {
    --primary-color: #805ad5;
    --secondary-color: #6b46c1;
    --bg-primary: linear-gradient(135deg, #805ad5 0%, #6b46c1 100%);
}

/* Font Family Variations */
[data-font="Poppins"] {
    --font-family: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

[data-font="Roboto"] {
    --font-family: 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

/* Font Size Variations */
[data-font-size="small"] {
    --font-size-base: 0.875rem;
    --font-size-lg: 1rem;
    --font-size-xl: 1.125rem;
}

[data-font-size="large"] {
    --font-size-base: 1.125rem;
    --font-size-lg: 1.25rem;
    --font-size-xl: 1.375rem;
}

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

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

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    min-height: 100vh;
    overflow-x: hidden;
}

/* ===== AUTHENTICATION STYLES ===== */
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-primary);
    padding: var(--spacing-md);
}

.auth-page {
    display: none;
    width: 100%;
    max-width: 400px;
}

.auth-page.active {
    display: block;
    animation: fadeInUp 0.6s ease;
}

.auth-card {
    background: var(--bg-secondary);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--border-color);
}

.auth-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.auth-icon {
    font-size: var(--font-size-3xl);
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

.auth-header h1 {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.auth-header p {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
}

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

.form-group {
    position: relative;
}

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

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: var(--spacing-md);
    padding-left: 2.5rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    transition: var(--transition-normal);
}

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

.form-icon {
    position: absolute;
    left: var(--spacing-md);
    top: 2.2rem;
    color: var(--text-muted);
    font-size: var(--font-size-sm);
}

.password-toggle {
    position: absolute;
    right: var(--spacing-md);
    top: 2.2rem;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: var(--font-size-sm);
    transition: var(--transition-fast);
}

.password-toggle:hover {
    color: var(--primary-color);
}

.auth-btn {
    width: 100%;
    padding: var(--spacing-md);
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--text-light);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-normal);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.auth-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.auth-footer {
    text-align: center;
    margin-top: var(--spacing-lg);
}

.auth-footer p {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
}

.auth-footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition-fast);
}

.auth-footer a:hover {
    text-decoration: underline;
}

/* ===== MAIN APPLICATION STYLES ===== */
.app-container {
    display: flex;
    min-height: 100vh;
    background: var(--bg-primary);
}

.app-container.hidden {
    display: none;
}

/* ===== SIDEBAR STYLES ===== */
.sidebar {
    width: 280px;
    background: var(--bg-secondary);
    backdrop-filter: blur(20px);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: fixed;
    left: 0;
    top: 0;
    height: 100vh;
    z-index: var(--z-fixed);
    transform: translateX(-100%);
    transition: var(--transition-normal);
}

.sidebar.open {
    transform: translateX(0);
}

.sidebar-header {
    padding: var(--spacing-xl);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

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

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-light);
    font-size: var(--font-size-lg);
}

.user-details h3 {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.user-details p {
    font-size: var(--font-size-xs);
    color: var(--text-muted);
}

.close-sidebar {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: var(--font-size-lg);
    cursor: pointer;
    padding: var(--spacing-sm);
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

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

.sidebar-nav {
    flex: 1;
    padding: var(--spacing-lg);
    overflow-y: auto;
    max-height: calc(100vh - 120px);
}

.nav-section {
    margin-bottom: var(--spacing-xl);
}

.nav-section h4 {
    font-size: var(--font-size-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: var(--spacing-md);
}

.nav-section ul {
    list-style: none;
}

.nav-section li {
    margin-bottom: var(--spacing-xs);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: var(--radius-md);
    transition: var(--transition-fast);
    font-size: var(--font-size-sm);
}

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

.nav-link.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--text-light);
}

.nav-link i {
    width: 16px;
    text-align: center;
}

.add-category-btn {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-tertiary);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-muted);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.add-category-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background: rgba(102, 126, 234, 0.05);
}

/* ===== MAIN CONTENT STYLES ===== */
.main-content {
    flex: 1;
    margin-left: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.app-header {
    background: var(--bg-secondary);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-lg) var(--spacing-xl);
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
}

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

.menu-toggle {
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: var(--font-size-lg);
    cursor: pointer;
    padding: var(--spacing-sm);
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

.menu-toggle:hover {
    background: var(--bg-tertiary);
}

.page-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--text-primary);
}

.header-right .stats {
    display: flex;
    gap: var(--spacing-lg);
}

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

.stat-number {
    display: block;
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    font-size: var(--font-size-xs);
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* ===== PAGE CONTENT STYLES ===== */
.page-content {
    flex: 1;
    padding: var(--spacing-xl);
    overflow-y: auto;
}

.page {
    display: none;
    max-width: 800px;
    margin: 0 auto;
}

.page.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

.page-header {
    margin-bottom: var(--spacing-2xl);
    text-align: center;
}

.page-header h2 {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.page-header p {
    color: var(--text-secondary);
    font-size: var(--font-size-base);
}

/* ===== TASK INPUT STYLES ===== */
.task-input-section {
    background: var(--bg-secondary);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.input-wrapper {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.task-input {
    flex: 1;
    padding: var(--spacing-md) var(--spacing-lg);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    transition: var(--transition-normal);
}

.task-input:focus {
    outline: none;
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.add-btn {
    padding: var(--spacing-md) var(--spacing-lg);
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--text-light);
    border: none;
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    cursor: pointer;
    transition: var(--transition-normal);
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 50px;
}

.add-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.category-select {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: var(--transition-fast);
}

.category-select:focus {
    outline: none;
    border-color: var(--border-focus);
}

.important-toggle {
    padding: var(--spacing-sm);
    background: none;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-muted);
    cursor: pointer;
    transition: var(--transition-fast);
    font-size: var(--font-size-base);
}

.important-toggle:hover {
    border-color: var(--warning-color);
    color: var(--warning-color);
}

.important-toggle.active {
    border-color: var(--warning-color);
    background: var(--warning-color);
    color: var(--text-light);
}

/* ===== FILTER SECTION STYLES ===== */
.filter-section {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.filter-buttons {
    display: flex;
    gap: var(--spacing-sm);
}

.filter-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: var(--transition-fast);
}

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

.filter-btn.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-color: var(--primary-color);
    color: var(--text-light);
}

.clear-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--danger-color);
    color: var(--text-light);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.clear-btn:hover {
    background: #c53030;
    transform: translateY(-1px);
}

.clear-btn:disabled {
    background: var(--text-muted);
    cursor: not-allowed;
    transform: none;
}

/* ===== TASK LIST STYLES ===== */
.tasks-container {
    background: var(--bg-secondary);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.task-list {
    list-style: none;
}

.task-item {
    display: flex;
    align-items: center;
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition-fast);
    background: var(--bg-tertiary);
}

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

.task-item:hover {
    background: var(--bg-secondary);
}

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

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

.task-checkbox {
    width: 24px;
    height: 24px;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    background: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: var(--spacing-md);
    transition: var(--transition-fast);
    color: transparent;
}

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

.task-item.completed .task-checkbox {
    background: var(--success-color);
    border-color: var(--success-color);
    color: var(--text-light);
}

.task-content {
    flex: 1;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.task-text {
    flex: 1;
    font-size: var(--font-size-base);
    color: var(--text-primary);
    line-height: 1.5;
}

.task-category {
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-size: var(--font-size-xs);
    font-weight: 500;
    color: var(--text-light);
    margin-right: var(--spacing-sm);
}

.task-important {
    color: var(--warning-color);
    font-size: var(--font-size-sm);
    margin-right: var(--spacing-sm);
}

.task-actions {
    display: flex;
    gap: var(--spacing-sm);
    opacity: 0;
    transition: var(--transition-fast);
}

.task-item:hover .task-actions {
    opacity: 1;
}

.task-action {
    padding: var(--spacing-sm);
    background: none;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition-fast);
    font-size: var(--font-size-sm);
}

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

.edit-btn:hover {
    background: rgba(56, 178, 172, 0.1);
}

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

.delete-btn:hover {
    background: rgba(229, 62, 62, 0.1);
}

/* ===== PROFILE & SETTINGS STYLES ===== */
.profile-content,
.settings-content {
    background: var(--bg-secondary);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

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

.settings-section {
    margin-bottom: var(--spacing-2xl);
}

.settings-section h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--border-color);
}

.setting-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid var(--border-color);
}

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

.setting-item label {
    font-weight: 500;
    color: var(--text-primary);
}

.setting-select {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    cursor: pointer;
    min-width: 120px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    cursor: pointer;
}

.checkbox-label input[type="checkbox"] {
    display: none;
}

.checkmark {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
}

.checkbox-label input[type="checkbox"]:checked + .checkmark {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

.checkbox-label input[type="checkbox"]:checked + .checkmark::after {
    content: '\f00c';
    font-family: 'Font Awesome 6 Free';
    font-weight: 900;
    color: var(--text-light);
    font-size: var(--font-size-xs);
}

.save-btn {
    padding: var(--spacing-md) var(--spacing-xl);
    background: linear-gradient(135deg, var(--success-color), #38a169);
    color: var(--text-light);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-normal);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    align-self: flex-start;
}

.save-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
    animation: fadeIn 0.3s ease;
}

.modal-content {
    background: var(--bg-secondary);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--border-color);
    width: 90%;
    max-width: 400px;
    animation: slideInUp 0.3s ease;
}

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

.modal-header h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
}

.modal-close {
    background: none;
    border: none;
    font-size: var(--font-size-xl);
    color: var(--text-muted);
    cursor: pointer;
    transition: var(--transition-fast);
}

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

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

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

.color-picker input[type="color"] {
    width: 50px;
    height: 40px;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
}

.color-options {
    display: flex;
    gap: var(--spacing-sm);
}

.color-option {
    width: 30px;
    height: 30px;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    cursor: pointer;
    transition: var(--transition-fast);
}

.color-option:hover {
    transform: scale(1.1);
    border-color: var(--text-primary);
}

.color-option[data-color="#667eea"] { background: #667eea; }
.color-option[data-color="#48bb78"] { background: #48bb78; }
.color-option[data-color="#ed8936"] { background: #ed8936; }
.color-option[data-color="#e53e3e"] { background: #e53e3e; }
.color-option[data-color="#9f7aea"] { background: #9f7aea; }
.color-option[data-color="#38b2ac"] { background: #38b2ac; }

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

.cancel-btn {
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: var(--transition-fast);
}

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

/* ===== SIDEBAR OVERLAY ===== */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-overlay);
    z-index: var(--z-modal-backdrop);
}

.sidebar-overlay.active {
    display: block;
}

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

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

@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(50px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

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

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

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        max-width: 320px;
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .app-header {
        padding: var(--spacing-md) var(--spacing-lg);
    }
    
    .page-content {
        padding: var(--spacing-lg);
    }
    
    .task-input-section {
        padding: var(--spacing-lg);
    }
    
    .input-wrapper {
        flex-direction: column;
    }
    
    .task-options {
        flex-direction: column;
        align-items: stretch;
    }
    
    .filter-section {
        flex-direction: column;
        gap: var(--spacing-md);
        align-items: stretch;
    }
    
    .filter-buttons {
        justify-content: center;
        flex-wrap: wrap;
    }
    
    .header-right .stats {
        gap: var(--spacing-md);
    }
    
    .stat-number {
        font-size: var(--font-size-lg);
    }
    
    .task-item {
        padding: var(--spacing-md);
    }
    
    .task-actions {
        opacity: 1;
    }
    
    .auth-card {
        padding: var(--spacing-xl);
    }
    
    .modal-content {
        margin: var(--spacing-md);
        padding: var(--spacing-xl);
    }
}

@media (max-width: 480px) {
    .page-header h2 {
        font-size: var(--font-size-xl);
    }
    
    .page-title {
        font-size: var(--font-size-lg);
    }
    
    .task-input-section {
        padding: var(--spacing-md);
    }
    
    .task-item {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-sm);
    }
    
    .task-content {
        width: 100%;
    }
    
    .task-actions {
        align-self: flex-end;
    }
    
    .filter-buttons {
        gap: var(--spacing-xs);
    }
    
    .filter-btn {
        padding: var(--spacing-xs) var(--spacing-sm);
        font-size: var(--font-size-xs);
    }
}

/* ===== UTILITY CLASSES ===== */
.hidden {
    display: none !important;
}

.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); }

/* ===== PRINT STYLES ===== */
@media print {
    .sidebar,
    .menu-toggle,
    .task-actions,
    .add-btn,
    .filter-section,
    .auth-container {
        display: none !important;
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .page-content {
        padding: 0;
    }
    
    .task-item {
        break-inside: avoid;
        border: 1px solid #ccc;
        margin-bottom: 0.5rem;
    }
}

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

@media (prefers-color-scheme: dark) {
    :root {
        --bg-primary: linear-gradient(135deg, #1a202c 0%, #2d3748 100%);
        --bg-secondary: rgba(45, 55, 72, 0.95);
        --bg-tertiary: rgba(45, 55, 72, 0.8);
        --text-primary: #f7fafc;
        --text-secondary: #e2e8f0;
        --text-muted: #a0aec0;
        --border-color: rgba(255, 255, 255, 0.1);
    }
}

/* Focus styles for accessibility */
*:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

button:focus,
input:focus,
select:focus,
textarea:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --border-color: #000;
        --text-muted: #333;
    }
    
    .task-item {
        border: 2px solid #000;
    }
    
    .nav-link:hover {
        background: #000;
        color: #fff;
    }
}