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

:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #edf5ff;
    --bg-hover: #e2e8f0;
    --text-primary: #1e293b;
    --text-secondary: #a0a0a0;
    --accent-primary: #0f4ba5;
    --accent-hover: #005a9e;
    --border-color: #e2e8f0;
    --success-color: #4caf50;
    --warning-color: #ff9800;
    --error-color: #f44336;
}

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

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

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

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

.logo svg {
    color: var(--accent-primary);
}

.logo h1 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    border: none;
    border-radius: 6px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

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

.btn-text {
    background: transparent;
    color: var(--text-secondary);
    padding: 6px 12px;
}

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

.theme-select {
    padding: 8px 12px;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 13px;
    cursor: pointer;
}

.theme-select:focus {
    outline: none;
    border-color: var(--accent-primary);
}

/* Toolbar */
.toolbar {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 10px 20px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    overflow-x: auto;
}

.tool-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: transparent;
    border: none;
    border-radius: 6px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s ease;
}

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

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

.toolbar .separator {
    width: 1px;
    height: 24px;
    background: var(--border-color);
    margin: 0 8px;
}

/* Main Content */
.main-content {
    display: flex;
    flex: 1;
    overflow: hidden;
}

.editor-pane,
.preview-pane {
    display: flex;
    flex-direction: column;
    min-width: 300px;
}

.editor-pane {
    flex: 1;
}

.preview-pane {
    flex: 1;
}

.pane-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 16px;
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-color);
    font-size: 14px;
    color: var(--text-secondary);
}

.stats-bar {
    display: flex;
    gap: 20px;
    padding: 8px 16px;
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-color);
    font-size: 12px;
    color: var(--text-secondary);
}

.stats-bar span {
    display: flex;
    align-items: center;
    gap: 4px;
}

.file-type {
    font-size: 11px;
    padding: 4px 8px;
    background: var(--bg-hover);
    border-radius: 4px;
    text-transform: none;
}

.view-options {
    display: flex;
    gap: 4px;
}

.view-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    background: transparent;
    border: none;
    border-radius: 4px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s ease;
}

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

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

/* Editor */
#editor {
    flex: 1;
    padding: 16px;
    background: var(--bg-primary);
    color: var(--text-primary);
    border: none;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 14px;
    line-height: 1.6;
    resize: none;
    outline: none;
    tab-size: 4;
}

#editor::placeholder {
    color: var(--text-secondary);
}

/* Resize Handle */
.resize-handle {
    width: 4px;
    background: var(--border-color);
    cursor: col-resize;
    transition: background 0.2s ease;
}

.resize-handle:hover {
    background: var(--accent-primary);
}

.resize-handle.resizing {
    background: var(--accent-primary);
}

/* Preview */
.preview-content {
    flex: 1;
    padding: 24px;
    overflow-y: auto;
    background: var(--bg-primary);
}

/* Preview Themes */
.preview-content.default {
    color: var(--text-primary);
}

.preview-content.github {
    color: #24292f;
    background: #ffffff;
}

.preview-content.minimal {
    color: #333;
    background: #fafafa;
}

.preview-content.dark {
    color: #1e293b;
    background: #ffffff;
}

/* Markdown Styles */
.preview-content h1,
.preview-content h2,
.preview-content h3,
.preview-content h4,
.preview-content h5,
.preview-content h6 {
    margin: 24px 0 16px;
    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: 0.875em;
    color: var(--text-secondary);
}

.preview-content p {
    margin: 12px 0;
    line-height: 1.6;
}

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

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

.preview-content strong {
    font-weight: 600;
}

.preview-content em {
    font-style: italic;
}

.preview-content code {
    padding: 2px 6px;
    background: var(--bg-tertiary);
    border-radius: 4px;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 0.875em;
}

.preview-content pre {
    margin: 16px 0;
    padding: 16px;
    background: var(--bg-secondary);
    border-radius: 8px;
    overflow-x: auto;
}

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

.preview-content blockquote {
    margin: 16px 0;
    padding: 12px 20px;
    border-left: 4px solid var(--accent-primary);
    background: var(--bg-tertiary);
    color: var(--text-secondary);
}

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

.preview-content li {
    margin: 8px 0;
}

.preview-content ul ul,
.preview-content ol ol,
.preview-content ul ol,
.preview-content ol ul {
    margin: 8px 0;
}

.preview-content hr {
    margin: 24px 0;
    border: none;
    border-top: 2px solid var(--border-color);
}

.preview-content img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
}

.preview-content table {
    width: 100%;
    margin: 16px 0;
    border-collapse: collapse;
}

.preview-content th,
.preview-content td {
    padding: 10px 14px;
    border: 1px solid var(--border-color);
    text-align: left;
}

.preview-content th {
    background: var(--bg-tertiary);
    font-weight: 600;
}

.preview-content tr:nth-child(even) {
    background: var(--bg-secondary);
}

.preview-content tr:hover {
    background: var(--bg-hover);
}

/* GitHub Theme Overrides */
.preview-content.github h1,
.preview-content.github h2 {
    border-color: #d0d7de;
}

.preview-content.github a {
    color: #0969da;
}

.preview-content.github code {
    background: #f6f8fa;
}

.preview-content.github pre {
    background: #f6f8fa;
}

.preview-content.github blockquote {
    background: #f6f8fa;
    border-color: #0969da;
    color: #57606a;
}

.preview-content.github th,
.preview-content.github td {
    border-color: #d0d7de;
}

.preview-content.github th {
    background: #f6f8fa;
}

.preview-content.github tr:nth-child(even) {
    background: #f6f8fa;
}

/* Minimal Theme Overrides */
.preview-content.minimal h1,
.preview-content.minimal h2 {
    border: none;
}

.preview-content.minimal code {
    background: #f0f0f0;
}

.preview-content.minimal pre {
    background: #f0f0f0;
}

.preview-content.minimal blockquote {
    background: transparent;
    border-left-color: #ccc;
}

/* Dark Theme Overrides */
.preview-content.dark a {
    color: #58a6ff;
}

.preview-content.dark code {
    background: #f8fafc;
}

.preview-content.dark pre {
    background: #f8fafc;
}

.preview-content.dark blockquote {
    background: #f8fafc;
    border-left-color: #58a6ff;
    color: #8b949e;
}

.preview-content.dark th,
.preview-content.dark td {
    border-color: #e2e8f0;
}

.preview-content.dark th {
    background: #f8fafc;
}

.preview-content.dark tr:nth-child(even) {
    background: #f8fafc;
}

.preview-content.dark tr:hover {
    background: #1f242c;
}

/* Footer */
.footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 20px;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    font-size: 12px;
}

.stats {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
}

.stats .separator {
    color: var(--border-color);
}

.actions {
    display: flex;
    gap: 8px;
}

/* Scrollbar Styles */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--bg-hover);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: #5a5a5e;
}

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

/* Responsive */
@media (max-width: 768px) {
    .header {
        padding: 10px 16px;
    }
    
    .logo h1 {
        font-size: 16px;
    }
    
    .btn span {
        display: none;
    }
    
    .btn {
        padding: 8px;
    }
    
    .toolbar {
        padding: 8px 12px;
    }
    
    .main-content {
        flex-direction: column;
    }
    
    .resize-handle {
        width: 100%;
        height: 4px;
        cursor: row-resize;
    }
    
    .preview-content {
        padding: 16px;
    }
    
    .footer {
        flex-direction: column;
        gap: 10px;
        text-align: center;
    }
}

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

/* Full width preview mode */
.preview-only .editor-pane {
    display: none;
}

.preview-only .resize-handle {
    display: none;
}

.preview-only .preview-pane {
    flex: 1 !important;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 60px;
    right: 20px;
    padding: 12px 20px;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    font-size: 14px;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.3s ease;
    z-index: 1000;
}

.toast.show {
    opacity: 1;
    transform: translateY(0);
}

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

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