The Moodle orange does not have a high enough contrast on a white or light grey background: https://app.moodle.net. It needs to either be on a dark background, or perhaps having a dark border around each letter instead. See: https://webaim.org/resources/contrastchecker/?fcolor=F98012&bcolor=E9EBEE

The border is a suggestion from the W3C: “add a thin black outline (at least one pixel wide) around the letter in order to keep the contrast ratio between the letter and the background above 4.5:1.”: https://www.w3.org/TR/2014/NOTE-WCAG20-TECHS-20140916/G18