:root{--bg: #0b1020;--panel: #fff;--accent: #2563eb;--border: #e2e8f0}body{margin:0;font-family:sans-serif;background:var(--bg);overflow:auto}.toolbar{display:flex;flex-wrap:wrap;gap:8px;background:var(--panel);padding:8px;border-bottom:1px solid var(--border)}.toolbar h3{margin:0;font-size:14px;color:var(--accent)}.button{padding:6px 10px;background:#fff;border:1px solid var(--border);border-radius:6px;cursor:pointer}.button.active{background:var(--accent);color:#fff}.canvas-container{display:flex;justify-content:center;margin-top:10px}