Selection Corner Brackets

Selection corner brackets, four slim smooth rounded L strokes (legs 0.03 m, 0.004 m thick) at a rectangle's corners; width and height (0.04-1.2 m, default 0.2) move them without resizing; the accent glows along them. Hover steps them slightly out.

风格：low-poly, flat-shaded vertex colors, no textures, 2 materials: the shared opaque one plus a distinct surface (glass, water or chrome), which stays its own mesh through mergeAssets rather than merging into the rest; shares palette and scale with its kit