This document is an English translation of the “freee Accessibility Guidelines.” The normative version of this document is in Japanese, and the English version is informational. The English translation is incomplete, and any links with their link texts left in Japanese are untranslated. Please be aware that there may be inaccuracies in the translation or parts that are outdated.

Importance of Contrast Ratio

When the contrast ratio between the foreground color and the background color of text and images is extremely low, it makes the content difficult to use for the majority of users who access the Web visually. Among users with low vision, some are particularly affected by low contrast ratios.

In our guidelines, we require a certain level of contrast ratio for visually presented information. The criteria we specify adhere to the success criteria of WCAG 2.1 at Level AA, although in our guidelines, we consider them as success criteria corresponding to Level A, and compliance is mandatory.

This applies to both text and images, including icons and images of text. For text, the criteria vary depending on factors such as font size and typeface.

For images, it is also necessary to ensure a sufficient contrast ratio with adjacent areas.