[iwoplaza]

The hero effect outputs premultiplied colors brighter than their alpha, so compositing over the page background went above 1.0. On EDR displays this switched the monitor to HDR and made the plum brighter than the white background in light mode.

The output is now clamped against the page background color, so it never composites above white. The look is otherwise unchanged.

[github-actions]

pkg.pr.new

No packages changed since release

[github-actions]

Bundle size comparison (import * as ... in PR vs import * as ... in target):

🟢 Decreased	➖ Unchanged	🔴 Increased	❔ Unknown
0	355	0	0

No notable changes.

If you wish to run a comparison for other, slower bundlers, run the 'Tree-shake test' from the GitHub Actions menu.

[github-actions]

Resolution Time Benchmark

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  line [1.03, 2.12, 4.65, 6.98, 8.10, 13.11, 27.66, 26.18]

Loading

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  line [0.31, 0.50, 0.71, 0.93, 1.23, 1.28, 1.51, 1.71]
  line [0.30, 0.51, 0.74, 0.93, 1.18, 1.27, 1.49, 1.67]

Loading

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  line [0.90, 2.21, 4.40, 7.57, 15.73, 28.28, 61.03, 120.96]

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[pullfrog]

✅ No new issues found.

Reviewed changes — full PR through d45bc1b (initial review; 2 commits, 1 file).

• Clamp the hero post-process output — saturates the mixed color, then clamps result.xyz to 1 - background * (1 - result.w). This keeps the premultiplied canvas (alphaMode: 'premultiplied') from compositing above the page background (color + background * (1 - alpha) > 1), which is what pushed EDR displays into HDR and made the plum brighter than white in light mode.
• Theme-aware background — adds a darkMode: u32 uniform, selects lightBackground = vec3f(1) (bg-white) or darkBackground = vec3f(35/255, 39/255, 54/255) (Tailwind --color-navy-bg, verified #232736), and writes/reads dataset.theme (the same attribute Starlight and CodeEditor.tsx use). The uniform is written per frame and destroyed in onCleanup.

Verified the compositing math holds (in light mode it reduces to color <= alpha, which is visually identical since a white background already clamps the result to white), and the generated WGSL resolves cleanly.

  ^{｜ View workflow run ｜ Using deepseek-v4.1-flash (free via Pullfrog for OSS) ｜ 𝕏}

[cieplypolar]

Suggested change

	let background = d.vec3f(lightBackground);
	if (darkMode.$ === 1) {
	background = d.vec3f(darkBackground);
	}
	const background = darkMode.$ === 1 ? d.vec3f(darkBackground) : d.vec3f(lightBackground);

[cieplypolar]

I am not sure if this is a good idea that the effect relies on undefined behavior (source).

Clamping against the page background does not guarantee that color <= alpha.
See:

Legend:

• x -> alpha
• y -> color
• b -> arbitrary channel from background color