Tab hover preview has incorrect origin

[Loskir]

Preliminary Checks

• I have read and understood the important section above.
• I have searched existing issues and avoided creating duplicates.
• I am not filing an enhancement request.
• I have checked that this issue cannot be reproduced on Mozilla Firefox.
• I have checked that this issue can be reproduced once I removed all my Mods and Custom CSS.

What happened?

Tab hover preview (#5875) animates from bottom left instead of top left

Here's relevant code:

desktop/src/zen/common/styles/zen-panel-ui.css

Lines 10 to 25 in 52a399f

	&[animate='open'] {
	animation: zen-jello-animation-macos 0.4s ease-out forwards;
	&[side='bottom'] {
	/* Animate from the bottom */
	-zen-window-transform-origin: 0 100%;
	}
	:root[zen-right-side='true'] & {
	/* Animate from the right */
	-zen-window-transform-origin: 100% 0;
	&[side='bottom'] {
	/* Animate from the bottom right */
	-zen-window-transform-origin: 100% 100%;
	}
	}
	}

It's either that -zen-window-transform-origin should be 0 0 or side=bottom is applied to the panel incorrectly.

Expected behavior

Preview animates from top left

Actual behavior

Preview animates from bottom left

Steps to reproduce

1. Enable tab hover preview (browser.tabs.hoverPreview.enabled)
2. Hover over a tab

Screenshots and videos

CleanShot.2025-08-31.at.20.31.52.mp4

Version

1.15.2b

What platform are you seeing the problem on?

macOS - aarch64

What component is this issue related to?

Tabs

Relevant log output if applicable