Remove long-outdated "star property hack"

[jeremywiebe]

Summary:

This PR removes an old CSS hack that are no longer relevant in our codebase (it's for IE7!)

Specifically, I noticed the CSS compiler balking at: *zoom: 1. So I asked the Genie about it and here's the explanation it gave.

The * in *zoom: 1; is a CSS hack called the "star property hack"
or "IE7 hack". It's used to target Internet Explorer 7 specifically.

Here's what it does:

• The * prefix makes the property only apply to Internet Explorer 7
  and earlier versions.
• Other browsers ignore properties that start with *.
• zoom: 1 is a Microsoft-specific CSS property that triggers
  "hasLayout" in IE, which is needed for certain layout behaviors
  to work correctly.

In this case, it's being used as part of a clearfix implementation.
The clearfix is a CSS technique to ensure that a container properly
contains its floated children. The *zoom: 1 ensures that IE7 properly
handles the layout of the clearfix container.

However, this hack is quite outdated since:

• Internet Explorer 7 was discontinued in 2015
• Modern browsers have much better CSS support
• There are cleaner ways to achieve the same layout effects today

The linter error you're seeing is likely because the linter doesn't
recognize the * prefix as valid CSS syntax, which is expected since
it's a browser-specific hack rather than standard CSS.

Issue:

Test plan:

I don't think this is a risky change as it's documented as being ignored by modern browsers and specifically for IE7!

[github-actions]

Size Change: 0 B

Total Size: 472 kB

ℹ️ View Unchanged

Filename	Size
packages/kas/dist/es/index.js	20.7 kB
packages/keypad-context/dist/es/index.js	1 kB
packages/kmath/dist/es/index.js	5.98 kB
packages/math-input/dist/es/index.js	98.6 kB
packages/math-input/dist/es/strings.js	1.61 kB
packages/perseus-core/dist/es/index.js	20.4 kB
packages/perseus-editor/dist/es/index.js	91.1 kB
packages/perseus-linter/dist/es/index.js	7.14 kB
packages/perseus-score/dist/es/index.js	9.23 kB
packages/perseus-utils/dist/es/index.js	403 B
packages/perseus/dist/es/index.js	200 kB
packages/perseus/dist/es/strings.js	7.56 kB
packages/pure-markdown/dist/es/index.js	1.22 kB
packages/simple-markdown/dist/es/index.js	6.72 kB

_{compressed-size-action}

[github-actions]

npm Snapshot: Published

Good news!! We've packaged up the latest commit from this PR (4817675) and published it to npm. You
can install it using the tag PR2628.

Example:

pnpm add @khanacademy/perseus@PR2628

If you are working in Khan Academy's frontend, you can run the below command.

./tools/bump_perseus_version.js -t PR2628

If you are working in Khan Academy's webapp, you can run the below command.

./dev/tools/bump_perseus_version.js -s n -t PR2628

[Copilot]

Pull Request Overview

Removes the outdated IE7-specific “star property hack” (*zoom: 1) from two style sheets, since modern browsers no longer require it.

• Delete legacy clearfix rule in radio.css
• Delete the same legacy clearfix rule in util.css

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
packages/perseus/src/styles/widgets/radio.css	Remove *zoom: 1 rule from the clearfix block
packages/perseus/src/styles/util.css	Remove *zoom: 1 rule from the clearfix block

Comments suppressed due to low confidence (2)

packages/perseus/src/styles/widgets/radio.css:11

• [nitpick] The .perseus-clearfix definition appears in multiple CSS files. Consider centralizing the clearfix rules into a shared utility stylesheet to avoid duplication and ease future updates.

}

packages/perseus/src/styles/widgets/radio.css:11

• Since this removes a layout-related hack, adding a visual regression test for the affected components (e.g., radio widget containers) can help catch any unintended layout shifts.

}

[benchristel]

Hyrum's Law at its finest 🙈. LGTM.