Accessibility in the context of a website or app means that it can be used by all people - regardless of whether the users live with a disability or not. Impairments can be either permanent characteristics (e.g. blindness) or situational circumstances (e.g. children's screams). Accessible design therefore considers contrast, alternative text for illustrations, subtitles for videos, etc. The German guideline for accessibility is the "Barrierefreie-Informationstechnik-Verordnung" (BITV 2.0). Internationally, the Web Content Accessibility Guidelines (WCAG 2.1) apply.