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

:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --border-color: #dee2e6;
    --accent-color: #4361ee;
    --accent-hover: #3a56d4;
    --success-color: #2ecc71;
    --danger-color: #e74c3c;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.12);
    --radius: 10px;
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-tertiary: #3d3d3d;
    --text-primary: #f8f9fa;
    --text-secondary: #adb5bd;
    --border-color: #495057;
    --accent-color: #5a7dff;
    --accent-hover: #6d8eff;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.35);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: var(--transition);
    min-height: 100vh;
}

.container {
    max-width: 1600px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    margin-bottom: 20px;
    border-bottom: 2px solid var(--border-color);
}

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

.logo i {
    font-size: 2.5rem;
    color: var(--accent-color);
}

.logo h1 {
    font-size: 2.2rem;
    font-weight: 700;
    background: linear-gradient(135deg, #4361ee, #9d4edd);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.version {
    background: var(--accent-color);
    color: white;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.controls {
    display: flex;
    align-items: center;
    gap: 20px;
}

.btn-icon {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 18px;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
    font-family: inherit;
    font-size: 1rem;
}

.btn-icon:hover {
    background: var(--accent-color);
    color: white;
    transform: translateY(-2px);
}

.word-count {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 18px;
    background: var(--bg-tertiary);
    border-radius: var(--radius);
    font-weight: 600;
}

.word-count i {
    color: var(--accent-color);
}

.toolbar {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    padding: 18px;
    background: var(--bg-primary);
    border-radius: var(--radius);
    margin-bottom: 25px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.toolbar-group {
    display: flex;
    gap: 10px;
    padding-right: 15px;
    border-right: 2px solid var(--border-color);
}

.toolbar-group:last-child {
    border-right: none;
}

.toolbar-btn {
    width: 42px;
    height: 42px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    cursor: pointer;
    font-size: 1.1rem;
    transition: var(--transition);
    font-family: inherit;
}

.toolbar-btn:hover {
    background: var(--accent-color);
    color: white;
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(67, 97, 238, 0.3);
}

.toolbar-btn.success:hover {
    background: var(--success-color);
}

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

.editor-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    flex: 1;
    margin-bottom: 25px;
}

@media (max-width: 1100px) {
    .editor-container {
        grid-template-columns: 1fr;
        grid-template-rows: 1fr 1fr;
    }
}

.editor-section, .preview-section {
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 18px 25px;
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-color);
}

.section-header h2 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.4rem;
}

.btn-sm {
    padding: 8px 16px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: inherit;
    font-size: 0.95rem;
}

.btn-sm:hover {
    background: var(--accent-color);
    color: white;
    transform: translateY(-2px);
}

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

.editor {
    flex: 1;
    padding: 25px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 16px;
    line-height: 1.7;
    background: var(--bg-primary);
    color: var(--text-primary);
    border: none;
    resize: none;
    outline: none;
    transition: var(--transition);
}

.editor::placeholder {
    color: var(--text-secondary);
    opacity: 0.7;
}

.preview {
    flex: 1;
    padding: 25px;
    overflow-y: auto;
    background: var(--bg-primary);
    transition: var(--transition);
}

#preview h1, #preview h2, #preview h3, #preview h4 {
    margin-top: 1.5em;
    margin-bottom: 0.8em;
    font-weight: 700;
    color: var(--text-primary);
}

#preview h1 {
    font-size: 2.2em;
    border-bottom: 3px solid var(--accent-color);
    padding-bottom: 0.3em;
}

#preview h2 {
    font-size: 1.8em;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.3em;
}

#preview p {
    margin-bottom: 1.2em;
}

#preview ul, #preview ol {
    margin-bottom: 1.2em;
    padding-left: 2em;
}

#preview li {
    margin-bottom: 0.5em;
}

#preview blockquote {
    border-left: 4px solid var(--accent-color);
    padding-left: 1.2em;
    margin: 1.5em 0;
    color: var(--text-secondary);
    font-style: italic;
}

#preview pre {
    background: var(--bg-tertiary);
    padding: 1.2em;
    border-radius: 8px;
    overflow-x: auto;
    margin: 1.5em 0;
    border: 1px solid var(--border-color);
}

#preview code {
    font-family: 'JetBrains Mono', monospace;
    background: var(--bg-tertiary);
    padding: 0.2em 0.4em;
    border-radius: 4px;
    font-size: 0.9em;
}

#preview pre code {
    background: none;
    padding: 0;
}

#preview table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5em 0;
}

#preview th, #preview td {
    border: 1px solid var(--border-color);
    padding: 0.8em;
    text-align: left;
}

#preview th {
    background: var(--bg-tertiary);
    font-weight: 700;
}

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

#preview a {
    color: var(--accent-color);
    text-decoration: none;
    border-bottom: 1px dashed var(--accent-color);
}

#preview a:hover {
    border-bottom-style: solid;
}

#preview img {
    max-width: 100%;
    border-radius: 8px;
    margin: 1em 0;
}

#preview hr {
    border: none;
    height: 2px;
    background: var(--border-color);
    margin: 2em 0;
}

.footer {
    margin-top: auto;
    padding: 25px 0 15px;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.footer-info p {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.footer-info i {
    margin-right: 6px;
    color: var(--accent-color);
}

.footer-links {
    display: flex;
    gap: 20px;
}

.footer-link {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

.footer-link:hover {
    color: var(--accent-color);
    transform: translateY(-2px);
}

::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

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

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

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

@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }
    
    .editor-container {
        gap: 15px;
    }
    
    .toolbar {
        justify-content: center;
    }
    
    .toolbar-group {
        border-right: none;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}