SIA-R91Letter spacing in style attributes is not !important

Accessibility requirements

This rule tests conformance of the following accessibility requirements:

Description

This rule checks that the style attribute is not used to prevent adjusting letter-spacing by using !important, except if it's at least 0.12 times the font size.

Applicability

This rule applies to every element in the HTML namespace that is visible and for which the style attribute declares the letter-spacing CSS property.

Expectations

  1. For the element, one of the following is true:

An element has a wide enough letter spacing if the computed value of its letter-spacing property is at least 0.12 times the computed value of its font-size property.

Assumptions

This rule makes the following assumption:

  • There is no mechanism available on the page to adjust letter-spacing.

Accessibility support

While some assistive technologies are able to set user origin or user agent origin styles, others, such as browser extensions, are only able to set styles with the author origin. Such assistive technologies cannot create styles "winning" the cascade sort over a style attribute with an important declaration. If accessibility support does not include assistive technologies that override letter-spacing through author origin, this rule should not be used.

Acknowledgments

This document includes material copied from or derived from https://act-rules.github.io/rules/24afc2/. Copyright © 2021 W3C® (MIT, ERCIM, Keio, Beihang).