theme-ui (https://theme-ui.com/getting-started https://theme-ui.com/getting-started), mui's `Theme` (https://mui.com/material-ui/customization/default-theme/ ht

theme-ui (https://theme-ui.com/getting-started https://theme-ui.com/getting-started), mui's `Theme` (https://mui.com/material-ui/customization/default-theme/ https://mui.com/material-ui/customization/default-theme/), bootstrap's variables Basically, when you think in purpose instead of colors.