refactor: use chakra styles instead of standard css

[mds1]

In #76 we introduced some styling, but it would be better to do this the chakra-native way

A Chakra native way to do this would be to use.

Global styles: https://chakra-ui.com/docs/styled-system/global-styles#how-it-works
layerStyles: https://chakra-ui.com/docs/styled-system/text-and-layer-styles#layer-styles

Only benefit is consistency so could make sense to push work to a future pr.

h/t @alexkeating