A **theme** controls how a published experience looks to learners —
colours, type and accent. Build themes once and apply them to any
experience.

## Contrast

The theme editor includes a contrast checker. Use it. An accent that
looks smart on your monitor can be unreadable on a phone in a kitchen,
and text that fails contrast is text some of your learners cannot
read at all.

## Light and dark

Learners can view in either. Check both — a colour that sits well on
white can vanish on a dark background.

## Availability

Custom themes are included from the Growth plan upwards.