/* ============================================
   CSS Variables & Theme Configuration
   ============================================ */
:root {
    /* Light Theme */
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #64748b;
    --secondary-hover: #475569;

    /* Colors */
    --background: #ffffff;
    --surface: #f8fafc;
    --surface-hover: #f1f5f9;
    --border: #e2e8f0;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;

    /* Status Colors */
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --danger: #dc2626;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

    /* 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-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;

    /* Font Family */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

    /* Z-index */
    --z-dropdown: 100;
    --z-modal: 1000;
    --z-toast: 2000;
}

/* Dark Theme */
[data-theme="dark"] {
    --background: #0f172a;
    --surface: #1e293b;
    --surface-hover: #334155;
    --border: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #64748b;
}

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

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

body {
    font-family: var(--font-family);
    background-color: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* ============================================
   Layout
   ============================================ */
.header {
    background-color: var(--background);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 10;
    transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.header-content {
    max-width: 100%;
    margin: 0 auto;
    padding: var(--spacing-md) var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.app-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    transition: color var(--transition-normal);
}

.app-title .icon {
    font-size: 1.75rem;
}

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

.language-select {
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background-color: var(--surface);
    color: var(--text-primary);
    font-size: 0.875rem;
    cursor: pointer;
    transition: border-color var(--transition-fast), background-color var(--transition-normal), color var(--transition-normal);
    min-width: 150px;
}

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

.language-select:hover {
    border-color: var(--text-secondary);
}


.main {
    flex: 1;
    display: grid;
    grid-template-columns: 320px 1fr;
    max-width: 100%;
    min-height: calc(100vh - 140px);
    gap: 1px;
    background-color: var(--border);
}

@media (max-width: 1024px) {
    .main {
        grid-template-columns: 280px 1fr;
    }
}

@media (max-width: 768px) {
    .main {
        grid-template-columns: 1fr;
    }

    .sidebar {
        display: none;
    }

    .main.sidebar-open .sidebar {
        display: block;
    }
}

/* ============================================
   Sidebar
   ============================================ */
.sidebar {
    background-color: var(--background);
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    transition: background-color var(--transition-normal);
}

.search-box {
    position: relative;
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--border);
    transition: border-color var(--transition-normal);
}

.search-icon {
    position: absolute;
    left: 1.25rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    pointer-events: none;
}

#searchInput {
    width: 100%;
    padding: 0.75rem 0.75rem 0.75rem 2.75rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background-color: var(--surface);
    color: var(--text-primary);
    font-size: 0.875rem;
    transition: border-color var(--transition-fast), background-color var(--transition-normal), color var(--transition-normal);
}

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

/* ============================================
   Buttons
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: 0.625rem 1rem;
    border: none;
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-icon {
    padding: 0.625rem;
    background: transparent;
    color: var(--text-secondary);
}

.btn-icon:hover:not(:disabled) {
    background-color: var(--surface-hover);
    color: var(--text-primary);
}

.btn-icon:active:not(:disabled) {
    transform: scale(0.95);
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: var(--surface);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-secondary:hover:not(:disabled) {
    background-color: var(--surface-hover);
    border-color: var(--text-secondary);
}

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

.btn-danger:hover:not(:disabled) {
    background-color: #b91c1c;
}

.btn-link {
    background: none;
    color: var(--primary);
    padding: 0;
}

.btn-link:hover {
    text-decoration: underline;
}

.btn-full {
    width: 100%;
}

/* ============================================
   Categories
   ============================================ */
.categories {
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--border);
    transition: border-color var(--transition-normal);
}

.categories h3 {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
}

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

.category-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 0.625rem 0.875rem;
    border: none;
    border-radius: var(--radius-md);
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.875rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    width: 100%;
    text-align: left;
}

.category-btn:hover {
    background-color: var(--surface-hover);
    color: var(--text-primary);
}

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

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

.category-count {
    margin-left: auto;
    padding: 0.125rem 0.5rem;
    background-color: var(--surface);
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 500;
    min-width: 1.5rem;
    text-align: center;
    transition: background-color var(--transition-fast);
}

.category-btn.active .category-count {
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
}

/* ============================================
   Notes List
   ============================================ */
.notes-section {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.notes-header {
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-sm);
    transition: border-color var(--transition-normal);
}

.notes-header h3 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.sort-select {
    padding: 0.375rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background-color: var(--surface);
    color: var(--text-primary);
    font-size: 0.75rem;
    cursor: pointer;
    transition: border-color var(--transition-fast), background-color var(--transition-normal), color var(--transition-normal);
}

.notes-list {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-sm);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.note-card {
    padding: var(--spacing-md);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background-color: var(--background);
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
}

.note-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.note-card.active {
    border-color: var(--primary);
    background-color: var(--surface);
}

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

.note-card-title {
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-primary);
    line-height: 1.4;
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    transition: color var(--transition-normal);
}

.note-card-pinned {
    color: var(--warning);
    flex-shrink: 0;
}

.note-card-preview {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    line-height: 1.5;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    margin-bottom: var(--spacing-sm);
    transition: color var(--transition-normal);
}

.note-card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-sm);
}

.note-card-category {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    font-size: 0.75rem;
    color: var(--text-muted);
}

.note-card-date {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* ============================================
   Empty States
   ============================================ */
.empty-state {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-2xl);
    text-align: center;
    color: var(--text-muted);
}

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

.empty-state p {
    font-size: 1rem;
    margin-bottom: var(--spacing-md);
}

/* ============================================
   Editor Section
   ============================================ */
.editor-section {
    background-color: var(--background);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: background-color var(--transition-normal);
}

.editor-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.editor-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: var(--spacing-lg);
    transition: border-color var(--transition-normal);
}

.note-title {
    flex: 1;
    padding: 0;
    border: none;
    background: transparent;
    font-size: 1.875rem;
    font-weight: 700;
    color: var(--text-primary);
    font-family: inherit;
    line-height: 1.2;
    transition: color var(--transition-normal);
}

.note-title::placeholder {
    color: var(--text-muted);
}

.note-title:focus {
    outline: none;
}

.editor-actions {
    display: flex;
    gap: var(--spacing-xs);
}

.note-meta {
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    transition: border-color var(--transition-normal);
}

.category-select {
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background-color: var(--surface);
    color: var(--text-primary);
    font-size: 0.875rem;
    cursor: pointer;
    transition: border-color var(--transition-fast), background-color var(--transition-normal), color var(--transition-normal);
}

.note-stats {
    display: flex;
    gap: var(--spacing-md);
    font-size: 0.8125rem;
    color: var(--text-muted);
}

/* ============================================
   Editor Toolbar
   ============================================ */
.editor-toolbar {
    padding: var(--spacing-sm) var(--spacing-lg);
    border-bottom: 1px solid var(--border);
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    align-items: center;
    transition: border-color var(--transition-normal);
}

.toolbar-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2rem;
    height: 2rem;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.toolbar-btn:hover {
    background-color: var(--surface-hover);
    color: var(--text-primary);
}

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

.toolbar-btn strong {
    font-size: 0.875rem;
}

.toolbar-divider {
    width: 1px;
    height: 1.5rem;
    background-color: var(--border);
    margin: 0 var(--spacing-xs);
    transition: background-color var(--transition-normal);
}

/* ============================================
   Note Content
   ============================================ */
.note-content {
    flex: 1;
    padding: var(--spacing-lg);
    overflow-y: auto;
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-primary);
    min-height: 400px;
}

.note-content:empty::before {
    content: attr(placeholder);
    color: var(--text-muted);
    pointer-events: none;
}

.note-content:focus {
    outline: none;
}

/* Rich text styling */
.note-content h1,
.note-content h2,
.note-content h3,
.note-content h4 {
    margin: var(--spacing-lg) 0 var(--spacing-sm) 0;
    font-weight: 600;
    color: var(--text-primary);
}

.note-content h1 { font-size: 2rem; }
.note-content h2 { font-size: 1.5rem; }
.note-content h3 { font-size: 1.25rem; }

.note-content p {
    margin-bottom: var(--spacing-md);
}

.note-content ul,
.note-content ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

.note-content li {
    margin-bottom: var(--spacing-xs);
}

.note-content a {
    color: var(--primary);
    text-decoration: underline;
}

.note-content blockquote {
    border-left: 4px solid var(--primary);
    padding-left: var(--spacing-md);
    margin: var(--spacing-md) 0;
    color: var(--text-secondary);
    font-style: italic;
}

.note-content code {
    background-color: var(--surface);
    padding: 0.125rem 0.375rem;
    border-radius: var(--radius-sm);
    font-family: monospace;
    font-size: 0.875em;
}

.note-content pre {
    background-color: var(--surface);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin-bottom: var(--spacing-md);
}

.note-content pre code {
    background: transparent;
    padding: 0;
}

/* ============================================
   Auto-save Indicator
   ============================================ */
.auto-save {
    padding: var(--spacing-sm) var(--spacing-lg);
    border-top: 1px solid var(--border);
    text-align: right;
    font-size: 0.75rem;
    color: var(--text-muted);
    transition: border-color var(--transition-normal);
}

#saveIndicator.saving {
    color: var(--warning);
}

/* ============================================
   Empty Editor
   ============================================ */
.empty-editor {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-2xl);
    text-align: center;
    color: var(--text-muted);
}

.empty-editor .empty-icon {
    font-size: 5rem;
    margin-bottom: var(--spacing-lg);
}

.empty-editor h2 {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    transition: color var(--transition-normal);
}

.empty-editor p {
    font-size: 1rem;
    margin-bottom: var(--spacing-xl);
    max-width: 400px;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background-color: var(--background);
    border-top: 1px solid var(--border);
    padding: var(--spacing-md) var(--spacing-lg);
    transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.footer-content {
    max-width: 100%;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.footer-content p {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.footer-info {
    display: flex;
    gap: var(--spacing-md);
    font-size: 0.875rem;
    color: var(--text-muted);
}

@media (max-width: 640px) {
    .footer-content {
        flex-direction: column;
        text-align: center;
    }

    .footer-info {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
}

/* ============================================
   SEO Content Styling
   ============================================ */
.seo-content {
    background-color: var(--surface);
    padding: var(--spacing-2xl) 0;
    border-top: 1px solid var(--border);
    transition: background-color var(--transition-normal);
}

.seo-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.seo-main-title {
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--text-primary);
    text-align: center;
    margin-bottom: var(--spacing-lg);
    line-height: 1.2;
    transition: color var(--transition-normal);
}

.seo-intro {
    font-size: 1.125rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    transition: color var(--transition-normal);
}

.seo-content h2 {
    font-size: 1.875rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-md);
    line-height: 1.3;
    transition: color var(--transition-normal);
}

.seo-content h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    line-height: 1.4;
    transition: color var(--transition-normal);
}

.seo-content h4 {
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    transition: color var(--transition-normal);
}

.seo-content p {
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    transition: color var(--transition-normal);
}

.seo-content strong {
    color: var(--primary);
    font-weight: 600;
}

.seo-features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
}

.seo-feature-card {
    background-color: var(--background);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    transition: all var(--transition-normal);
}

.seo-feature-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.seo-feature-card h3 {
    margin-top: 0;
    margin-bottom: var(--spacing-md);
    font-size: 1.25rem;
}

.seo-list {
    list-style: none;
    padding: 0;
    margin: var(--spacing-md) 0;
}

.seo-list li {
    padding: var(--spacing-sm) 0;
    position: relative;
    padding-left: var(--spacing-xl);
    color: var(--text-secondary);
    line-height: 1.6;
    transition: color var(--transition-normal);
}

.seo-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary);
    font-weight: bold;
}

.seo-use-cases {
    display: grid;
    gap: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
}

@media (min-width: 768px) {
    .seo-use-cases {
        grid-template-columns: repeat(2, 1fr);
    }
}

.seo-use-case {
    background-color: var(--background);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    transition: all var(--transition-normal);
}

.seo-use-case:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-md);
}

.seo-use-case h4 {
    margin-top: 0;
    margin-bottom: var(--spacing-md);
    font-size: 1.125rem;
}

.seo-comparison {
    overflow-x: auto;
    margin: var(--spacing-xl) 0;
}

.seo-table {
    width: 100%;
    border-collapse: collapse;
    background-color: var(--background);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.seo-table thead {
    background-color: var(--surface);
}

.seo-table th {
    padding: var(--spacing-md);
    text-align: left;
    font-weight: 600;
    color: var(--text-primary);
    border-bottom: 2px solid var(--primary);
    transition: color var(--transition-normal);
}

.seo-table td {
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--border);
    color: var(--text-secondary);
    transition: color var(--transition-normal);
}

.seo-table tbody tr:hover {
    background-color: var(--surface-hover);
}

.seo-faq {
    margin: var(--spacing-xl) 0;
}

.faq-item {
    background-color: var(--background);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-md);
    border: 1px solid var(--border);
    transition: all var(--transition-normal);
}

.faq-item:hover {
    border-color: var(--primary);
}

.faq-item h4 {
    margin-top: 0;
    margin-bottom: var(--spacing-md);
    font-size: 1.125rem;
    color: var(--text-primary);
}

.faq-item p {
    margin-bottom: 0;
}

.seo-cta {
    font-size: 1.125rem;
    text-align: center;
    padding: var(--spacing-xl);
    background-color: var(--background);
    border-radius: var(--radius-lg);
    border: 2px solid var(--primary);
    color: var(--text-primary);
    font-weight: 600;
    margin-top: var(--spacing-2xl);
    transition: all var(--transition-normal);
}

.seo-cta:hover {
    background-color: var(--primary);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

@media (max-width: 768px) {
    .seo-main-title {
        font-size: 1.75rem;
    }

    .seo-content h2 {
        font-size: 1.5rem;
    }

    .seo-content h3 {
        font-size: 1.25rem;
    }

    .seo-features-grid {
        grid-template-columns: 1fr;
    }

    .seo-use-cases {
        grid-template-columns: 1fr;
    }

    .seo-container {
        padding: 0 var(--spacing-md);
    }
}

/* ============================================
   Toast Notifications
   ============================================ */
.toast-container {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    z-index: var(--z-toast);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.toast {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    background-color: var(--background);
    box-shadow: var(--shadow-xl);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 0.875rem;
    animation: slideIn 0.3s ease;
    max-width: 400px;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

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

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

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

.toast.info {
    border-left: 4px solid var(--primary);
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes slideOut {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(100%);
        opacity: 0;
    }
}

/* ============================================
   Modal
   ============================================ */
.modal {
    display: none;
    position: fixed;
    inset: 0;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: var(--z-modal);
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
}

.modal.active {
    display: flex;
}

.modal-content {
    background-color: var(--background);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    max-width: 400px;
    width: 100%;
    box-shadow: var(--shadow-xl);
    animation: modalIn 0.3s ease;
    transition: background-color var(--transition-normal);
}

@keyframes modalIn {
    from {
        transform: scale(0.9);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

.modal-content h2 {
    font-size: 1.25rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    transition: color var(--transition-normal);
}

.modal-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.6;
}

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

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

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

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

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

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 640px) {
    .header-content {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .app-title span:not(.icon) {
        display: none;
    }

    .editor-header {
        flex-direction: column;
        gap: var(--spacing-md);
    }

    .note-title {
        font-size: 1.5rem;
        width: 100%;
    }

    .editor-toolbar {
        padding: var(--spacing-sm);
    }

    .note-content {
        padding: var(--spacing-md);
    }

    .toast-container {
        left: var(--spacing-md);
        right: var(--spacing-md);
        bottom: var(--spacing-md);
    }

    .toast {
        max-width: 100%;
    }
}

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

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.fade-in {
    animation: fadeIn 0.3s ease;
}

/* ============================================
   RTL (Right-to-Left) Support
   ============================================ */
html[dir="rtl"] {
    direction: rtl;
    text-align: right;
}

html[dir="rtl"] .header-content {
    flex-direction: row;
}

html[dir="rtl"] .app-title .icon {
    margin-left: 0;
    margin-right: var(--spacing-sm);
}

html[dir="rtl"] .header-actions {
    flex-direction: row-reverse;
}

html[dir="rtl"] .note-title,
html[dir="rtl"] #noteContent {
    text-align: right;
}

html[dir="rtl"] .search-icon {
    left: auto;
    right: 1.25rem;
}

html[dir="rtl"] #searchInput {
    padding-left: 0.75rem;
    padding-right: 2.75rem;
}

html[dir="rtl"] .category-btn .category-count {
    margin-left: 0;
    margin-right: auto;
}

html[dir="rtl"] .note-card-category {
    margin-left: 0;
    margin-right: auto;
}

html[dir="rtl"] .toolbar-btn strong {
    font-family: inherit;
}

html[dir="rtl"] .modal-actions {
    flex-direction: row-reverse;
}

/* ============================================
   Print Styles
   ============================================ */
@media print {
    .header,
    .sidebar,
    .footer,
    .editor-toolbar,
    .editor-actions,
    .auto-save {
        display: none !important;
    }

    .main {
        display: block;
    }

    .editor-section {
        border: none;
    }

    .note-content {
        overflow: visible;
    }

    body {
        background-color: white;
        color: black;
    }
}

/* ============================================
   SEO Content Section Styles
   ============================================ */
.seo-content {
    background-color: var(--background);
    padding: var(--spacing-2xl) var(--spacing-lg);
    border-top: 1px solid var(--border);
    max-width: 900px;
    margin: 0 auto;
    transition: background-color var(--transition-normal);
}

.seo-container {
    max-width: 800px;
    margin: 0 auto;
}

.seo-main-title {
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
    text-align: center;
    line-height: 1.2;
    transition: color var(--transition-normal);
}

.seo-intro {
    font-size: 1.125rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

.seo-content h2 {
    font-size: 1.75rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-lg);
    line-height: 1.3;
    transition: color var(--transition-normal);
}

.seo-content h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    transition: color var(--transition-normal);
}

.seo-content h4 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    transition: color var(--transition-normal);
}

.seo-content p {
    font-size: 1rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

.seo-content strong {
    color: var(--primary);
    font-weight: 600;
}

.seo-content a {
    color: var(--primary);
    text-decoration: underline;
}

.seo-content a:hover {
    color: var(--primary-hover);
}

/* Features Grid */
.seo-features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
}

.seo-feature-card {
    background-color: var(--surface);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    transition: all var(--transition-normal);
}

.seo-feature-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--primary);
}

.seo-feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

/* Lists */
.seo-list {
    list-style: none;
    padding: 0;
    margin: var(--spacing-md) 0;
}

.seo-list li {
    padding: var(--spacing-sm) 0;
    padding-left: 2rem;
    position: relative;
    line-height: 1.7;
    color: var(--text-secondary);
}

.seo-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary);
    font-weight: bold;
}

.seo-list ol li::before {
    content: counter(list-item);
}

.seo-content ol {
    list-style: decimal;
    padding-left: 2rem;
    margin: var(--spacing-md) 0;
    line-height: 1.8;
    color: var(--text-secondary);
}

.seo-content ol li {
    padding: var(--spacing-sm) 0;
}

/* Use Cases */
.seo-use-cases {
    margin: var(--spacing-xl) 0;
    display: grid;
    gap: var(--spacing-lg);
}

.seo-use-case {
    background-color: var(--surface);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    border-left: 4px solid var(--primary);
}

.seo-use-case h4 {
    font-size: 1.125rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

/* Comparison Table */
.seo-comparison {
    overflow-x: auto;
    margin: var(--spacing-xl) 0;
}

.seo-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.95rem;
}

.seo-table thead {
    background-color: var(--primary);
    color: white;
}

.seo-table th {
    padding: var(--spacing-md);
    text-align: left;
    font-weight: 600;
}

.seo-table td {
    padding: var(--spacing-md);
    border: 1px solid var(--border);
}

.seo-table tbody tr:nth-child(even) {
    background-color: var(--surface);
}

/* FAQ Section */
.seo-faq {
    margin: var(--spacing-xl) 0;
}

.faq-item {
    background-color: var(--surface);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
    border: 1px solid var(--border);
}

.faq-item h4 {
    font-size: 1.125rem;
    color: var(--primary);
    margin-bottom: var(--spacing-sm);
}

.faq-item p {
    margin: 0;
}

/* CTA */
.seo-cta {
    font-size: 1.125rem;
    text-align: center;
    padding: var(--spacing-lg);
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-hover) 100%);
    color: white !important;
    border-radius: var(--radius-lg);
    margin-top: var(--spacing-xl);
}

.seo-cta strong {
    color: white !important;
}

/* Responsive */
@media (max-width: 768px) {
    .seo-content {
        padding: var(--spacing-xl) var(--spacing-md);
    }

    .seo-main-title {
        font-size: 1.75rem;
    }

    .seo-content h2 {
        font-size: 1.5rem;
    }

    .seo-content h3 {
        font-size: 1.25rem;
    }

    .seo-features-grid {
        grid-template-columns: 1fr;
    }

    .seo-use-cases {
        grid-template-columns: 1fr;
    }

    .seo-table {
        font-size: 0.875rem;
    }

    .seo-table th,
    .seo-table td {
        padding: var(--spacing-sm);
    }
}

@media (max-width: 480px) {
    .seo-main-title {
        font-size: 1.5rem;
    }

    .seo-content h2 {
        font-size: 1.25rem;
    }

    .seo-content h3,
    .seo-content h4 {
        font-size: 1.125rem;
    }

    .seo-content p {
        font-size: 0.95rem;
    }
}