Build a self-contained, no-build-step index.html that shows several visual states or variants side by side — new SVG/CSS art states, design options, before/after — so the user can open it directly in a browser and look. Use when the user asks to "see" a visual change, asks "where is the index.html", points at an existing reference/<thing>/index.html as the pattern to follow, or when a change is SVG/CSS art that has no live page to preview it on yet.
