:root{--bg-primary: #0d1117;--bg-secondary: #161b22;--bg-tertiary: #21262d;--text-primary: #f0f6fc;--text-secondary: #8b949e;--border-color: #30363d;--accent-color: #238636;--accent-hover: #2ea043;--btn-secondary-bg: #21262d;--btn-secondary-hover: #30363d;--link-color: #58a6ff;--font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif;--font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace}@media(prefers-color-scheme:light){:root:not([data-theme=dark]){--bg-primary: #ffffff;--bg-secondary: #f6f8fa;--bg-tertiary: #eaeef2;--text-primary: #1f2328;--text-secondary: #656d76;--border-color: #d0d7de;--btn-secondary-bg: #f6f8fa;--btn-secondary-hover: #eff1f3;--link-color: #0969da}}[data-theme=light]{--bg-primary: #ffffff;--bg-secondary: #f6f8fa;--bg-tertiary: #eaeef2;--text-primary: #1f2328;--text-secondary: #656d76;--border-color: #d0d7de;--btn-secondary-bg: #f6f8fa;--btn-secondary-hover: #eff1f3;--link-color: #0969da}[data-theme=dark]{--bg-primary: #0d1117;--bg-secondary: #161b22;--bg-tertiary: #21262d;--text-primary: #f0f6fc;--text-secondary: #8b949e;--border-color: #30363d;--btn-secondary-bg: #21262d;--btn-secondary-hover: #30363d;--link-color: #58a6ff}*{box-sizing:border-box;margin:0;padding:0}html,body{height:100%;font-family:var(--font-sans);background-color:var(--bg-primary);color:var(--text-primary);overflow:hidden;transition:background-color .2s ease,color .2s ease}#app{display:flex;flex-direction:column;height:100vh}.app-header{height:52px;background-color:var(--bg-secondary);border-bottom:1px solid var(--border-color);display:flex;align-items:center;justify-content:space-between;padding:0 16px;-webkit-user-select:none;user-select:none;flex-shrink:0}.brand{display:flex;align-items:center;gap:8px;font-weight:600;font-size:1.1rem;color:var(--text-primary)}.brand-logo{font-size:1.2rem}.toolbar-actions{display:flex;align-items:center;gap:10px}.toolbar-item{display:flex;align-items:center;gap:6px;font-size:.85rem;color:var(--text-secondary)}.select-input{height:32px;box-sizing:border-box;background-color:var(--bg-tertiary);color:var(--text-primary);border:1px solid var(--border-color);padding:0 10px;border-radius:6px;font-size:.85rem;outline:none;cursor:pointer;vertical-align:middle}.btn{height:32px;box-sizing:border-box;display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:0 12px;border-radius:6px;font-size:.85rem;font-weight:500;border:1px solid var(--border-color);cursor:pointer;transition:all .15s ease;-webkit-user-select:none;user-select:none;vertical-align:middle}.btn-secondary{background-color:var(--btn-secondary-bg);color:var(--text-primary)}.btn-secondary:hover{background-color:var(--btn-secondary-hover)}.btn-primary{background-color:var(--accent-color);border-color:#f0f6fc1a;color:#fff}.btn-primary:hover{background-color:var(--accent-hover)}.split-container{flex:1;display:flex;flex-direction:row;overflow:hidden;position:relative}.pane{flex:1;display:flex;flex-direction:column;height:100%;overflow:hidden;background-color:var(--bg-primary)}.pane-editor{border-right:1px solid var(--border-color)}.pane-header{height:36px;background-color:var(--bg-secondary);border-bottom:1px solid var(--border-color);display:flex;align-items:center;padding:0 16px;font-size:.75rem;text-transform:uppercase;letter-spacing:.05em;color:var(--text-secondary);font-weight:600;-webkit-user-select:none;user-select:none}.editor-textarea{flex:1;width:100%;padding:16px;border:none;outline:none;resize:none;background-color:var(--bg-primary);color:var(--text-primary);font-family:var(--font-mono);font-size:.95rem;line-height:1.6;white-space:pre-wrap;word-wrap:break-word}.preview-body{flex:1;padding:24px;overflow-y:auto;line-height:1.6;font-size:1rem;color:var(--text-primary)}.preview-body h1,.preview-body h2,.preview-body h3,.preview-body h4{margin-top:1.2em;margin-bottom:.6em;font-weight:600;line-height:1.25}.preview-body h1{font-size:1.8rem;border-bottom:1px solid var(--border-color);padding-bottom:.3em}.preview-body h2{font-size:1.4rem;border-bottom:1px solid var(--border-color);padding-bottom:.3em}.preview-body p{margin-bottom:1em}.preview-body pre{background-color:var(--bg-tertiary);padding:14px;border-radius:6px;overflow-x:auto;font-family:var(--font-mono);font-size:.9rem;margin-bottom:1em;border:1px solid var(--border-color)}.preview-body code{font-family:var(--font-mono);font-size:.85em;background-color:var(--bg-tertiary);padding:2px 5px;border-radius:4px}.preview-body pre code{background:transparent;padding:0}.preview-body blockquote{border-left:4px solid var(--border-color);padding-left:14px;color:var(--text-secondary);margin-bottom:1em}.preview-body ul,.preview-body ol{padding-left:24px;margin-bottom:1em}.preview-body table{border-collapse:collapse;width:100%;margin-bottom:1em}.preview-body th,.preview-body td{border:1px solid var(--border-color);padding:8px 12px;text-align:left}.preview-body th{background-color:var(--bg-secondary)}.preview-body a{color:var(--link-color);text-decoration:none}.preview-body a:hover{text-decoration:underline}.status-bar{height:28px;background-color:var(--bg-secondary);border-top:1px solid var(--border-color);display:flex;align-items:center;justify-content:space-between;padding:0 16px;font-size:.75rem;color:var(--text-secondary);-webkit-user-select:none;user-select:none;flex-shrink:0}@media(max-width:768px){.split-container{flex-direction:column}.pane-editor{border-right:none;border-bottom:1px solid var(--border-color)}.toolbar-actions .btn-text{display:none}}