:root{--bg:#fafafa;--fg:#1e293b;--accent:#2563eb;--grid:#e5e7eb;--wire:#e8b800;--wire-cold:#888;--danger:#dc2626;--success:#16a34a}*{box-sizing:border-box}html,body,#root{height:100%;margin:0;padding:0}body{background:var(--bg);color:var(--fg);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif}.app-shell{grid-template-rows:56px 1fr;grid-template-columns:72px 1fr 320px;width:100%;height:100%;display:grid}.toolbar{border-bottom:1px solid var(--grid);background:#fff;grid-area:1/1/auto/-1;align-items:center;gap:8px;padding:0 16px;display:flex}.tray{border-right:1px solid var(--grid);background:#fff;flex-direction:column;grid-area:2/1;gap:4px;padding:8px;display:flex}.canvas-wrap{grid-area:2/2;position:relative;overflow:hidden}.canvas{touch-action:none;-webkit-user-select:none;user-select:none;width:100%;height:100%}.side{border-left:1px solid var(--grid);background:#fff;grid-area:2/3;overflow-y:auto}.tray-btn{border:1px solid var(--grid);cursor:pointer;background:#fff;border-radius:8px;justify-content:center;align-items:center;width:56px;height:56px;font-size:20px;display:flex}.tray-btn.active{background:var(--accent);color:#fff;border-color:var(--accent)}.tray-btn svg{margin:0 auto;display:block}.tray-btn.active svg{color:#fff}.toolbar button{border:1px solid var(--grid);cursor:pointer;background:#fff;border-radius:6px;margin-left:8px;padding:6px 12px}.inspector{padding:16px}.inspector .empty{color:#9ca3af;text-align:center;margin-top:24px;font-size:14px}.inspector h3{text-transform:capitalize;color:var(--fg);margin:0 0 12px;font-size:16px}.inspector label{color:#6b7280;text-transform:uppercase;letter-spacing:.04em;margin-bottom:4px;font-size:12px;font-weight:600;display:block}.inspector select{border:1px solid var(--grid);width:100%;color:var(--fg);cursor:pointer;background:#fff;border-radius:6px;margin-bottom:12px;padding:6px 8px;font-size:14px;display:block}.burned-banner{color:var(--danger);background:#fef2f2;border:1px solid #fca5a5;border-radius:6px;margin-top:8px;padding:8px 12px;font-size:13px}.inspector-delete{background:var(--danger);color:#fff;cursor:pointer;border:none;border-radius:6px;margin-top:16px;padding:8px 14px;font-size:14px;font-weight:600}.inspector-delete:hover{background:#b91c1c}.inspector-hint{color:#94a3b8;margin:6px 0 0;font-size:11px}.hover-tooltip{color:#fff;pointer-events:none;white-space:nowrap;background:#111827;border-radius:6px;padding:6px 12px;font-size:13px;box-shadow:0 4px 12px #0003}.multimeter{border-bottom:1px solid var(--grid);background:#f8fafc;padding:16px}.mm-display{color:#4ade80;text-align:center;background:#0f172a;border-radius:6px;padding:12px;font-family:Menlo,monospace;font-size:24px}.mm-hint{color:#475569;margin:8px 0;font-size:12px}.multimeter button{border:1px solid var(--grid);cursor:pointer;background:#fff;border-radius:6px;margin-top:4px;padding:6px 12px;font-size:13px}.gallery-overlay{z-index:1000;background:#0006;justify-content:center;align-items:center;display:flex;position:fixed;inset:0}.gallery{background:#fff;border-radius:12px;min-width:400px;max-height:80vh;padding:24px;overflow-y:auto}.gallery ul{margin:0;padding:0;list-style:none}.gallery li{border-bottom:1px solid var(--grid);align-items:center;gap:12px;padding:8px 0;display:flex}.gallery .open{cursor:pointer;text-align:left;color:var(--accent);background:0 0;border:none;flex:1;font-size:16px}.gallery .meta{color:#94a3b8;font-size:12px}.gallery .remove{color:var(--danger);border:1px solid var(--danger);cursor:pointer;background:0 0;border-radius:4px;padding:2px 8px}.challenge-panel{border-bottom:1px solid var(--grid);padding:16px}.challenge-panel h3{margin:0 0 12px}.challenge-panel ul{margin:0;padding:0;list-style:none}.challenge-panel li{padding:4px 0}.challenge-panel li button{cursor:pointer;text-align:left;color:var(--fg);background:0 0;border:none;border-radius:4px;width:100%;padding:4px 8px;font-size:14px}.challenge-panel li.active button{color:var(--accent);background:#dbeafe;font-weight:600}.challenge-panel li.completed button{color:var(--success)}.active-challenge{background:#f8fafc;border-radius:6px;margin-top:12px;padding:12px;font-size:14px}.hint{color:#475569;font-size:13px}.success-banner{background:var(--success);color:#fff;border-radius:6px;margin-bottom:12px;padding:12px}