The content and meaning of each page are not altered when the styles are disabled
Styles allow to give a shape to the background. Content must remain readable and understandable when this form cannot be seen or displayed.
Objectives
Allow reader content to be understood if reader/reader software does not apply style sheets embedded in the digital book or if access mode is not visual.
Improve accessibility of content to readers with disabilities.
Implementation
We will ensure that content in HTML files (i. e. Structure tags : h1, h2, p, and semantics : em, strong…), to present them in the same order and with the same sense with or without CSS formatting.
Control
Use ACE to check the logical structure of the content (“Structures” tab of the ACE report).
Make sure content stays readable, e.g. in the case of a transparent HTML image whose readability depends on the background color applied with the background-color property