GeezerVison

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/tools/notes/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
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• All existing tests are passing: https://github.com/NativeScript/NativeScript/blob/master/tools/notes/DevelopmentWorkflow.md#running-unit-tests-application.
• Tests for the changes are included - https://github.com/NativeScript/NativeScript/blob/master/tools/notes/WritingUnitTests.md.

What is the current behavior?

background: none changes nothing: the background parser does not accept the none keyword, so the shorthand fails to expand and none of the background longhands change. A native control such as a button keeps its own background (e.g. Bootstrap's .nav-link pills, or any CSS reset that clears button backgrounds).

What is the new behavior?

• The background parser reads none as the image component.
• The background shorthand maps it to no image and, unless the declaration also gives a color, to a transparent background-color, the initial value CSS resets it to.
• Shorthands that only give an image, repeat or position still leave background-color unset, so views keep their native default background behind an image (e.g. the iOS Page's white).

Tests: 3 parser cases in css/parser.spec.ts and 4 specs in ui/styling/style-properties.spec.ts. apps/automated gains test_setting_background_none_from_CSS_makes_backgroundColor_transparent.

Verified with all of these core PRs merged together (#11527–#11537): apps/automated passes on the iOS 26.4 simulator (1830 OK, 0 failed) and on an Android API 36 emulator (1692 OK; the one failure is the network-dependent IMAGE-CACHE.test_ImageCache_ValidUrl timeout, which also passes on reruns).