https://github.com/material-components/material-components-web/blame/8656bf0e032270f97d8673d33aaab4760befb5bc/packages/mdc-theme/_theme-color.scss#L66

Is this really neccessary? Why can it not work with css variables too? What happens if var(--my-primary-color) is passed in instead?

Can this code detect if it is a var and just resolve it and continue?