Invalid CSS for nested fullwidth layouts with zeroed-out custom padding

[richtabor]

An invalid CSS issue occurs when applying a padding rule of 0 to a full width group block, inside a full width group.

This creates an unwanted horizontal scroll, as the nested fullwidth value is not properly negated.

This is a result of resolving #60716, which ensured that the editor and front-end both negative margin for when custom padding is set. That works fine when a unit is also applied to a padding value, but when you set the padding to 0, the calc() function requires a unit—otherwise the CSS is invalid and the padding value is not applied, which results in horizontal scroll.

Visual

CleanShot.2024-07-11.at.09.20.11.mp4