:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafe;
    --bg-tertiary: #e8f2ff;
    --text-primary: #1a202c;
    --text-secondary: #4a5568;
    --text-muted: #718096;
    --border-color: #e2e8f0;
    --accent-color: #667eea;
    --accent-hover: #5a67d8;
    --success-color: #48bb78;
    --warning-color: #ed8936;
    --danger-color: #f56565;
    --info-color: #4299e1;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.1);
    --radius: 12px;
    --radius-sm: 6px;
    --font-mono: 'JetBrains Mono', 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, monospace;
    --font-size: 14px;
    --line-height: 1.6;
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-success: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

[data-theme="dark"] {
    --bg-primary: #0f0f23;
    --bg-secondary: #1a1a2e;
    --bg-tertiary: #16213e;
    --text-primary: #edf2f7;
    --text-secondary: #a0aec0;
    --text-muted: #718096;
    --border-color: #2d3748;
    --accent-color: #9f7aea;
    --accent-hover: #805ad5;
    --success-color: #68d391;
    --warning-color: #f6ad55;
    --danger-color: #fc8181;
    --info-color: #63b3ed;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.4);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.5);
    --gradient-primary: linear-gradient(135deg, #9f7aea 0%, #667eea 100%);
    --gradient-secondary: linear-gradient(135deg, #ed64a6 0%, #f093fb 100%);
    --gradient-success: linear-gradient(135deg, #38b2ac 0%, #4facfe 100%);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
    font-size: var(--font-size);
    line-height: var(--line-height);
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

/* Header */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 20px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    z-index: 100;
}

.app-title {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 18px;
    font-weight: 600;
    color: var(--accent-color);
}

.header-right {
    display: flex;
    gap: 8px;
}

/* Toolbar */
.toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 16px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
    gap: 8px;
}

.toolbar-section {
    display: flex;
    gap: 12px;
    align-items: center;
}

.toolbar-group {
    display: flex;
    gap: 4px;
    align-items: center;
    padding: 4px;
    background: var(--bg-primary);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
}

/* Buttons */
.btn {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 8px 12px;
    background: transparent;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    cursor: pointer;
    font-size: 13px;
    font-weight: 500;
    transition: all 0.2s ease;
    white-space: nowrap;
}

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

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

.btn-icon {
    padding: 8px;
    min-width: 32px;
    justify-content: center;
}

.btn-small {
    padding: 4px 8px;
    font-size: 12px;
}

/* Main Editor */
.editor-main {
    display: flex;
    flex: 1;
    overflow: hidden;
}

.editor-pane,
.preview-pane {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.editor-pane {
    border-right: 1px solid var(--border-color);
}

.pane-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    min-height: 48px;
}

.pane-title {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
}

.editor-stats {
    display: flex;
    gap: 12px;
    font-size: 11px;
    color: var(--text-muted);
}

.preview-controls {
    display: flex;
    gap: 4px;
}

/* Editor */
.editor-wrapper {
    flex: 1;
    position: relative;
    overflow: hidden;
}

#markdownInput {
    width: 100%;
    height: 100%;
    padding: 20px;
    border: none;
    outline: none;
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: var(--font-size);
    line-height: var(--line-height);
    resize: none;
    tab-size: 4;
}

#markdownInput::placeholder {
    color: var(--text-muted);
    opacity: 0.7;
}

/* Preview */
.preview-content {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
    background: var(--bg-primary);
}

.preview-content h1,
.preview-content h2,
.preview-content h3,
.preview-content h4,
.preview-content h5,
.preview-content h6 {
    margin: 24px 0 16px 0;
    font-weight: 600;
    line-height: 1.25;
}

.preview-content h1 { 
    font-size: 2em; 
    border-bottom: 2px solid var(--border-color); 
    padding-bottom: 8px; 
}

.preview-content h2 { 
    font-size: 1.5em; 
    border-bottom: 1px solid var(--border-color); 
    padding-bottom: 6px; 
}

.preview-content h3 { font-size: 1.25em; }
.preview-content h4 { font-size: 1.1em; }
.preview-content h5 { font-size: 1em; }
.preview-content h6 { 
    font-size: 0.9em; 
    color: var(--text-secondary); 
}

.preview-content p {
    margin: 16px 0;
    line-height: 1.7;
}

.preview-content ul,
.preview-content ol {
    margin: 16px 0;
    padding-left: 24px;
}

.preview-content li {
    margin: 6px 0;
    line-height: 1.6;
}

.preview-content blockquote {
    margin: 20px 0;
    padding: 16px 20px;
    border-left: 4px solid var(--accent-color);
    background: var(--bg-secondary);
    border-radius: 0 var(--radius) var(--radius) 0;
    font-style: italic;
}

.preview-content code {
    padding: 3px 6px;
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.9em;
    border: 1px solid var(--border-color);
}

.preview-content pre {
    margin: 20px 0;
    padding: 16px;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    overflow-x: auto;
    border: 1px solid var(--border-color);
}

.preview-content pre code {
    padding: 0;
    background: none;
    border-radius: 0;
    border: none;
}

.preview-content table {
    margin: 20px 0;
    border-collapse: collapse;
    width: 100%;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    overflow: hidden;
}

.preview-content th,
.preview-content td {
    padding: 12px 16px;
    border-bottom: 1px solid var(--border-color);
    text-align: left;
}

.preview-content th {
    background: var(--bg-secondary);
    font-weight: 600;
    border-bottom: 2px solid var(--border-color);
}

.preview-content tr:last-child td {
    border-bottom: none;
}

.preview-content a {
    color: var(--accent-color);
    text-decoration: none;
}

.preview-content a:hover {
    text-decoration: underline;
}

.preview-content img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius);
    margin: 12px 0;
    box-shadow: var(--shadow);
}

.preview-content hr {
    margin: 32px 0;
    border: none;
    border-top: 2px solid var(--border-color);
}

/* Status Bar */
.status-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 16px;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    font-size: 11px;
    color: var(--text-secondary);
    min-height: 32px;
}

.status-left,
.status-right {
    display: flex;
    gap: 16px;
    align-items: center;
}

.status-item {
    display: flex;
    align-items: center;
    gap: 4px;
}

.status-item a {
    color: var(--accent-color);
    text-decoration: none;
}

.status-item a:hover {
    text-decoration: underline;
}

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

#saveStatus.saved {
    color: var(--success-color);
}

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

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--bg-primary);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    max-width: 500px;
    width: 90%;
    max-height: 80vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

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

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-secondary);
}

.modal-header h3 {
    font-size: 16px;
    font-weight: 600;
}

.modal-close {
    font-size: 20px;
    font-weight: bold;
    padding: 4px 8px;
}

.modal-body {
    padding: 20px;
    overflow-y: auto;
}

/* Settings */
.setting-group {
    margin-bottom: 20px;
}

.setting-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
}

.setting-group input[type="range"] {
    width: 100%;
    margin: 8px 0;
}

.setting-group select {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--bg-primary);
    color: var(--text-primary);
}

.setting-group input[type="checkbox"] {
    margin-right: 8px;
}

/* Help */
.help-tabs {
    display: flex;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 20px;
}

.help-tab {
    padding: 12px 16px;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-weight: 500;
    border-bottom: 2px solid transparent;
}

.help-tab.active {
    color: var(--accent-color);
    border-bottom-color: var(--accent-color);
}

.help-panel {
    display: none;
}

.help-panel.active {
    display: block;
}

.shortcut-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 12px;
    margin-top: 16px;
}

.shortcut-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 12px;
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
}

.shortcut-item kbd {
    background: var(--bg-tertiary);
    padding: 2px 6px;
    border-radius: 3px;
    font-size: 11px;
    font-family: var(--font-mono);
}

.syntax-examples {
    margin-top: 16px;
}

.syntax-item {
    margin-bottom: 12px;
    padding: 12px;
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
}

.syntax-item code {
    display: block;
    margin-top: 4px;
    padding: 8px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
}

.contact-info {
    margin: 16px 0;
    padding: 16px;
    background: var(--bg-secondary);
    border-radius: var(--radius);
}

.support-links {
    display: flex;
    gap: 8px;
    margin-top: 16px;
}

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

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

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

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

/* Responsive */
@media (max-width: 768px) {
    .editor-main {
        flex-direction: column;
    }
    
    .editor-pane {
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }
    
    .toolbar {
        padding: 8px;
    }
    
    .toolbar-group {
        gap: 2px;
    }
    
    .btn {
        padding: 6px 8px;
        font-size: 12px;
    }
    
    .editor-stats {
        display: none;
    }
    
    .status-right {
        display: none;
    }
}

/* Animations */
* {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

.pulse {
    animation: pulse 0.3s ease;
}

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

.modal.active .modal-content {
    animation: fadeIn 0.3s ease;
}

/* Focus states */
#markdownInput:focus {
    box-shadow: inset 0 0 0 2px var(--accent-color);
}

.btn:focus {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

/* Loading states */
.loading {
    opacity: 0.7;
    pointer-events: none;
}

/* Print styles */
@media print {
    .app-header,
    .toolbar,
    .status-bar,
    .editor-pane {
        display: none !important;
    }
    
    .preview-pane {
        border: none !important;
    }
    
    .preview-content {
        padding: 0 !important;
    }
}