"The composes keyword says that .normal includes all the styles from .common, much like the @extends keyword in Sass. But while Sass rewrites your CSS selectors to make that happen, CSS Modules changes which classes are exported to JavaScript."
And isn't file (module) naming and directory structure what we use to organize regular code? I like the idea of going to the components folder and looking for the 'submit button' file when I need to alter something much more than searching a 20,000 line css file or randomly split scss files. Even nicer is the concept of including your styles in the same directory as the components they define, further mirroring normal code organization. It seems like this would allow for much easier onboarding into a project.