/* ===== CSS Reset & Base Styles ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Palette */
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --secondary-color: #6b7280;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    
    /* Priority Colors */
    --priority-high: #ef4444;
    --priority-medium: #f59e0b;
    --priority-low: #10b981;
    
    /* Background Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --bg-dark: #1f2937;
    
    /* Text Colors */
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    
    /* Border Colors */
    --border-color: #e5e7eb;
    --border-hover: #d1d5db;
    
    /* Shadows */
    --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);
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 250ms ease-in-out;
    --transition-slow: 350ms ease-in-out;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 16px;
    line-height: 1.5;
    color: var(--text-primary);
    background-color: var(--bg-secondary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===== Layout ===== */
.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== Header ===== */
.app-header {
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-xl);
    max-width: 1400px;
    margin: 0 auto;
}

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

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

.icon-btn {
    background: none;
    border: none;
    padding: var(--spacing-sm);
    cursor: pointer;
    border-radius: var(--radius-md);
    transition: background-color var(--transition-fast);
    font-size: 1.25rem;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.5rem;
    height: 2.5rem;
}

.icon-btn:hover {
    background-color: var(--bg-tertiary);
}

.icon-btn:active {
    transform: scale(0.95);
}

/* Search Bar */
.search-bar {
    padding: 0 var(--spacing-xl) var(--spacing-md);
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
}

.search-bar.hidden {
    display: none;
}

.search-bar input {
    flex: 1;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    transition: border-color var(--transition-fast);
}

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

.close-btn {
    background: none;
    border: none;
    padding: var(--spacing-sm);
    cursor: pointer;
    font-size: 1.25rem;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

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

/* ===== Main Content ===== */
.main-content {
    display: flex;
    flex: 1;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
    gap: var(--spacing-lg);
    padding: var(--spacing-lg);
}

/* ===== Sidebar ===== */
.sidebar {
    width: 250px;
    background-color: var(--bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    height: fit-content;
    position: sticky;
    top: calc(70px + var(--spacing-lg));
}

.nav-menu {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-xl);
}

.nav-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: none;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 0.95rem;
    color: var(--text-secondary);
    text-align: left;
    width: 100%;
}

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

.nav-item.active {
    background-color: var(--primary-color);
    color: white;
}

.nav-icon {
    font-size: 1.25rem;
}

.nav-label {
    font-weight: 500;
}

/* Folders Section */
.folders-section {
    border-top: 1px solid var(--border-color);
    padding-top: var(--spacing-lg);
}

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

.section-header h3 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.add-btn {
    background: none;
    border: none;
    width: 1.5rem;
    height: 1.5rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 1.25rem;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.folders-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.folder-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    color: var(--text-secondary);
}

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

.folder-item.active {
    background-color: rgba(59, 130, 246, 0.1);
    color: var(--primary-color);
}

.folder-icon {
    font-size: 1rem;
}

.folder-name {
    font-size: 0.9rem;
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.folder-count {
    font-size: 0.75rem;
    background-color: var(--bg-tertiary);
    padding: 0.125rem 0.5rem;
    border-radius: 1rem;
    color: var(--text-secondary);
}

/* ===== Content Area ===== */
.content-area {
    flex: 1;
    min-width: 0;
}

.view-section {
    display: none;
}

.view-section.active {
    display: block;
}

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

.view-header h2 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
}

/* ===== Buttons ===== */
.primary-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    box-shadow: var(--shadow-sm);
}

.primary-btn:hover {
    background-color: var(--primary-hover);
    box-shadow: var(--shadow-md);
}

.primary-btn:active {
    transform: scale(0.98);
}

.secondary-btn {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.danger-btn {
    background-color: var(--danger-color);
    color: white;
    border: none;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.btn-icon {
    font-size: 1.25rem;
}

/* ===== Items Grid ===== */
.items-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: var(--spacing-xl) var(--spacing-lg);
    color: var(--text-secondary);
}

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

.empty-state p {
    font-size: 1.1rem;
}

/* Note Card */
.note-card {
    background-color: var(--bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-fast);
    cursor: pointer;
    border: 1px solid var(--border-color);
}

.note-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

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

.note-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}

.note-content {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
}

.note-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.8rem;
    color: var(--text-light);
}

.note-date {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.note-folder-tag {
    background-color: var(--bg-tertiary);
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* To-Do Card */
.todo-card {
    background-color: var(--bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-fast);
    cursor: pointer;
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--priority-medium);
}

.todo-card.priority-high {
    border-left-color: var(--priority-high);
}

.todo-card.priority-medium {
    border-left-color: var(--priority-medium);
}

.todo-card.priority-low {
    border-left-color: var(--priority-low);
}

.todo-card.completed {
    opacity: 0.6;
}

.todo-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

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

.todo-checkbox {
    width: 1.25rem;
    height: 1.25rem;
    cursor: pointer;
    margin-top: 0.125rem;
    flex-shrink: 0;
}

.todo-content {
    flex: 1;
}

.todo-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

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

.todo-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}

.todo-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    font-size: 0.8rem;
}

.todo-deadline {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--text-light);
}

.todo-deadline.overdue {
    color: var(--danger-color);
    font-weight: 500;
}

.todo-priority-badge {
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 500;
    text-transform: uppercase;
}

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

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

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

/* Folder Card */
.folder-card {
    background-color: var(--bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-fast);
    cursor: pointer;
    border: 1px solid var(--border-color);
    text-align: center;
}

.folder-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.folder-card-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.folder-card-name {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.folder-card-count {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* ===== 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-lg);
    backdrop-filter: blur(4px);
}

.modal.active {
    display: flex;
}

.modal-content {
    background-color: var(--bg-primary);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    width: 100%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    animation: modalSlideIn 0.3s ease-out;
}

.modal-small {
    max-width: 400px;
}

@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;
    padding: var(--spacing-lg) var(--spacing-xl);
    border-bottom: 1px solid var(--border-color);
}

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

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

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

.modal-body {
    padding: var(--spacing-xl);
}

.modal-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg) var(--spacing-xl);
    border-top: 1px solid var(--border-color);
}

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

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

.form-group label {
    display: block;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.form-group input[type="text"],
.form-group input[type="datetime-local"],
.form-group input[type="color"],
.form-group select,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-family: inherit;
    transition: all var(--transition-fast);
    background-color: var(--bg-primary);
    color: var(--text-primary);
}

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

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

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

/* Voice Controls */
.voice-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-sm);
}

.voice-btn {
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 0.9rem;
    color: var(--text-primary);
}

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

.voice-btn.recording {
    background-color: var(--danger-color);
    color: white;
    border-color: var(--danger-color);
    animation: pulse 1.5s infinite;
}

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

.voice-icon {
    font-size: 1.125rem;
}

.voice-status {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* Color Picker */
.color-picker {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.color-picker input[type="text"] {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: monospace;
    font-size: 0.95rem;
}

/* ===== Settings ===== */
.settings-section {
    margin-bottom: var(--spacing-xl);
}

.settings-section:last-child {
    margin-bottom: 0;
}

.settings-section h4 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-md);
}

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

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

.setting-info label {
    display: block;
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.setting-description {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.setting-value {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.storage-status {
    font-size: 0.9rem;
    color: var(--success-color);
    font-weight: 500;
}

/* Toggle Switch */
.toggle-switch {
    position: relative;
    display: inline-block;
    width: 48px;
    height: 24px;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--border-color);
    transition: var(--transition-normal);
    border-radius: 24px;
}

.toggle-slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    transition: var(--transition-normal);
    border-radius: 50%;
}

.toggle-switch input:checked + .toggle-slider {
    background-color: var(--primary-color);
}

.toggle-switch input:checked + .toggle-slider:before {
    transform: translateX(24px);
}

.full-width {
    width: 100%;
    margin-top: var(--spacing-sm);
}

/* ===== Toast Notification ===== */
.toast {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    background-color: var(--bg-dark);
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    z-index: 2000;
    opacity: 0;
    transform: translateY(20px);
    transition: all var(--transition-normal);
    pointer-events: none;
    max-width: 400px;
}

.toast.show {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
}

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

.toast.error {
    background-color: var(--danger-color);
}

.toast.warning {
    background-color: var(--warning-color);
}

/* ===== Utility Classes ===== */
.hidden {
    display: none !important;
}

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
    .main-content {
        flex-direction: column;
    }
    
    .sidebar {
        width: 100%;
        position: static;
    }
    
    .nav-menu {
        flex-direction: row;
        overflow-x: auto;
    }
    
    .nav-item {
        flex-shrink: 0;
    }
}

@media (max-width: 768px) {
    .header-content {
        padding: var(--spacing-md);
    }
    
    .app-title {
        font-size: 1.25rem;
    }
    
    .main-content {
        padding: var(--spacing-md);
        gap: var(--spacing-md);
    }
    
    .sidebar {
        padding: var(--spacing-md);
    }
    
    .view-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-md);
    }
    
    .view-header h2 {
        font-size: 1.5rem;
    }
    
    .items-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .modal-content {
        max-width: 100%;
        margin: var(--spacing-md);
    }
    
    .modal-header,
    .modal-body,
    .modal-footer {
        padding: var(--spacing-md);
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .toast {
        bottom: var(--spacing-md);
        right: var(--spacing-md);
        left: var(--spacing-md);
        max-width: none;
    }
}

@media (max-width: 480px) {
    .app-title {
        font-size: 1.125rem;
    }
    
    .header-actions {
        gap: var(--spacing-xs);
    }
    
    .icon-btn {
        width: 2rem;
        height: 2rem;
        font-size: 1rem;
    }
    
    .nav-label {
        display: none;
    }
    
    .modal-actions {
        flex-direction: column;
        width: 100%;
    }
    
    .modal-actions button {
        width: 100%;
    }
}

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

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

button:focus-visible,
a:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}