[Solid] Color picker in controlled mode doesn't update blacks

[teidesu]

🐛 Bug report

Screen.Recording.2025-12-12.at.02.52.39.mov

💥 Steps to reproduce

1. open the ark-ui solid stackblitz demo
2. open the picker
3. click within the area and drag down, try moving the mouse left/right
4. notice how the color doesn't update

note that this doesn't reproduce in uncontrolled mode (i.e. using defaultValue)

💻 Link to reproduction

https://ark-ui.com/docs/components/color-picker#controlled, the Solid one

🧐 Expected behavior

the color updates normally

🧭 Possible Solution

the issue seems to lie in this equality check

zag/packages/machines/color-picker/src/color-picker.machine.ts

Lines 49 to 51 in 33393b7

	isEqual(a, b) {
	return a.toString("css") === b?.toString("css")
	},

when changing between technically the same color (black) but with different saturation, .toString("css") always returns hsla(0, 0%, 0%, 1) regardless of saturation:

a possible solution might be to replace css mode with hsb (since that's technically how the color is represented internally), but idk if that might break something else (e.g. with different color modes)

🌍 System information

Software	Version(s)
Zag Version	5.30.0
Browser	Chrome 142
Operating System	macOS

📝 Additional information

the issue can also be reproduced with svelte, vue and react seem to be fine