Trying to see if I messed something up, however I'm using the default theme with nothing added a to my default theme other than marking the scheme to dark. When I try to use any of the default yellow colors - it doesn't work, it just appears as white text. eg:
// usage
<Title order={2} color={theme.colors.yellow[4]} transform={'uppercase'}>
I should be yellow[4]
</Title>
Picture is attached