In general, the colour of text should contrast with the background. A bright colour on a dark background will show up well, as will a dark colour on a light background. You also need to make sure that the reader does not experience visual fatigue, which tends to happen if the colours are too vibrant.
Here are some examples of good and bad colour choices:
Source: https://www.lifewire.com/contrasting-foreground-background-colors-4061363
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