:root{--bg: #f4f6f9;--panel: #ffffff;--panel-border: #e3e8ef;--text: #1f2733;--text-muted: #697586;--accent: #2d6cff;--accent-soft: #e8f0ff;--danger: #d64545;--shadow: 0 6px 24px rgba(20, 32, 60, .12);--radius: 12px;--topbar-h: 52px;font-family:Inter,Segoe UI,system-ui,-apple-system,Helvetica Neue,Arial,sans-serif}*{box-sizing:border-box}html,body{margin:0;height:100%;overflow:hidden;background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased}button{font-family:inherit;cursor:pointer}#app{position:fixed;inset:0;display:flex;flex-direction:column}#topbar{height:var(--topbar-h);flex:0 0 auto;display:flex;align-items:center;justify-content:space-between;padding:0 12px;background:var(--panel);border-bottom:1px solid var(--panel-border);z-index:30}.brand{display:flex;align-items:center;gap:10px;min-width:0}.brand-mark{width:30px;height:30px;border-radius:8px;background:var(--accent);color:#fff;font-weight:700;display:grid;place-items:center;font-size:17px;flex:0 0 auto}.board-title{border:1px solid transparent;background:transparent;font-size:15px;font-weight:600;color:var(--text);padding:5px 8px;border-radius:8px;width:240px;max-width:46vw;outline:none}.board-title:hover{background:#f1f4f9}.board-title:focus{background:#fff;border-color:var(--accent)}.topbar-actions{display:flex;align-items:center;gap:4px}.divider{width:1px;height:22px;background:var(--panel-border);margin:0 6px}.icon-btn{width:34px;height:34px;border:none;border-radius:8px;background:transparent;color:var(--text-muted);display:grid;place-items:center;transition:background .12s,color .12s}.icon-btn svg{width:19px;height:19px;display:block}.icon-btn:hover{background:#eef1f6;color:var(--text)}.icon-btn.active{background:var(--accent-soft);color:var(--accent)}.icon-btn:disabled{opacity:.35;cursor:default;background:transparent}.text-btn{border:none;background:transparent;color:var(--text-muted);font-size:13px;font-weight:500;padding:7px 10px;border-radius:8px}.text-btn:hover{background:#eef1f6;color:var(--text)}.text-btn.danger:hover{background:#fdeaea;color:var(--danger)}#stage{position:relative;flex:1 1 auto;overflow:hidden}#board{position:absolute;inset:0;width:100%;height:100%;display:block;touch-action:none;background:var(--bg);cursor:default}#board.tool-hand{cursor:grab}#board.panning{cursor:grabbing}#board.tool-eraser,#board.tool-draw{cursor:crosshair}.element{cursor:default}.el-shape{vector-effect:non-scaling-stroke}.el-note-shadow{pointer-events:none}.el-text{user-select:none;pointer-events:none;dominant-baseline:hanging}.sel-frame{fill:none;stroke:var(--accent);stroke-width:1.5;pointer-events:none}.sel-handle{fill:#fff;stroke:var(--accent);stroke-width:1.5;cursor:pointer}.sel-rotate{fill:#fff;stroke:var(--accent);stroke-width:1.5;cursor:grab}.marquee{fill:#2d6cff14;stroke:var(--accent);stroke-width:1;stroke-dasharray:4 3}#toolbar{position:absolute;top:16px;left:16px;display:flex;flex-direction:column;gap:3px;padding:7px;background:var(--panel);border:1px solid var(--panel-border);border-radius:14px;box-shadow:var(--shadow);z-index:20}#toolbar .icon-btn{width:40px;height:40px}#toolbar .tool-sep{height:1px;background:var(--panel-border);margin:5px 4px}#inspector{position:absolute;top:16px;right:16px;width:244px;max-height:calc(100% - 32px);overflow-y:auto;padding:14px;background:var(--panel);border:1px solid var(--panel-border);border-radius:var(--radius);box-shadow:var(--shadow);z-index:20}#inspector.hidden{display:none}.insp-title{font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.04em;color:var(--text-muted);margin:0 0 10px}.insp-row{margin-bottom:14px}.insp-label{font-size:12px;font-weight:600;color:var(--text-muted);margin-bottom:7px;display:flex;justify-content:space-between}.swatches{display:grid;grid-template-columns:repeat(8,1fr);gap:6px}.swatch{width:100%;aspect-ratio:1;border-radius:6px;border:1px solid rgba(0,0,0,.12);cursor:pointer;padding:0;position:relative}.swatch.active{outline:2px solid var(--accent);outline-offset:1px}.swatch.none{background:linear-gradient(135deg,#fff 45%,#e0483f 46% 54%,#fff 55%)}.color-row{display:flex;align-items:center;gap:8px}input[type=color]{width:38px;height:30px;padding:0;border:1px solid var(--panel-border);border-radius:8px;background:#fff;cursor:pointer}input[type=range]{width:100%;accent-color:var(--accent)}.seg{display:flex;gap:3px;background:#eef1f6;border-radius:8px;padding:3px}.seg button{flex:1;border:none;background:transparent;border-radius:6px;padding:6px 0;font-size:12px;color:var(--text-muted);display:grid;place-items:center}.seg button svg{width:16px;height:16px}.seg button.active{background:#fff;color:var(--accent);box-shadow:0 1px 2px #00000014}.btn-grid{display:grid;grid-template-columns:1fr 1fr;gap:6px}.btn-grid button{border:1px solid var(--panel-border);background:#fff;border-radius:8px;padding:7px 6px;font-size:12px;color:var(--text)}.btn-grid button:hover{background:#f4f6f9;border-color:#cfd7e3}#zoom-controls{position:absolute;bottom:16px;left:16px;display:flex;align-items:center;gap:2px;padding:5px;background:var(--panel);border:1px solid var(--panel-border);border-radius:12px;box-shadow:var(--shadow);z-index:20}.zoom-label{border:none;background:transparent;color:var(--text);font-size:12.5px;font-weight:600;min-width:52px;padding:7px 4px;border-radius:8px}.zoom-label:hover{background:#eef1f6}#text-editor{position:absolute;z-index:25;margin:0;padding:0;border:none;outline:none;resize:none;overflow:hidden;background:transparent;line-height:1.25;color:#1f2733;font-family:inherit;box-shadow:0 0 0 2px var(--accent);border-radius:4px}#text-editor.hidden{display:none}.status{position:absolute;bottom:20px;left:50%;transform:translate(-50%) translateY(12px);background:#1f2733;color:#fff;font-size:13px;padding:9px 16px;border-radius:10px;opacity:0;pointer-events:none;transition:opacity .18s,transform .18s;z-index:40;white-space:nowrap}.status.show{opacity:1;transform:translate(-50%) translateY(0)}#help-overlay{position:absolute;inset:0;background:#0f172a59;display:grid;place-items:center;z-index:50}#help-overlay.hidden{display:none}.help-card{background:#fff;border-radius:16px;padding:24px 26px;width:min(520px,90vw);box-shadow:var(--shadow)}.help-card h2{margin:0 0 16px;font-size:17px}.help-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px 22px;margin-bottom:18px}.help-grid .row{display:flex;justify-content:space-between;gap:12px;font-size:13px;color:var(--text-muted)}.help-grid .row kbd{font-family:inherit;background:#eef1f6;border:1px solid var(--panel-border);border-bottom-width:2px;border-radius:6px;padding:1px 7px;font-size:11.5px;color:var(--text)}@media (max-width: 640px){#toolbar{top:auto;bottom:16px;left:50%;transform:translate(-50%);flex-direction:row;flex-wrap:wrap;max-width:92vw;justify-content:center}#toolbar .tool-sep{width:1px;height:auto;margin:4px 5px}#zoom-controls{bottom:78px}#inspector{inset:auto 12px 78px;width:auto;max-height:40vh}.board-title{width:120px}}