useColorModeValue

const { colorMode } = useColorMode()
const bg = useColorModeValue("blackAlpha.800", "whiteAlpha.800")
const color = useColorModeValue("whiteAlpha.800", "blackAlpha.800")

return (
  <Box
    bg={bg}
    p="md"
    rounded="md"
    color={color}
    transitionProperty="all"
    transitionDuration="normal"
  >
    The current colorMode is "{colorMode}"
  </Box>
)