It's funny: if a programmer is told to write CSS but doesn't know how, he'll copy-and-paste from Stack Overflow, get a shit result, and say that CSS sucks. If a programmer is told to write Elm but doesn't know how, he'll learn the language, write some decent Elm, and be happy. Now, who do you think will have the better time - the person that actually learned his tools or the person that copy-pasted CSS from Stack Overflow?
Even if you assume that CSS is as horrible as the author would have you believe, the 'solution' of Elm is preposterous. As another commenter [0] said: it outputs a crazy amount of divs, all the styles are inline, you lose the CSS ecosystem, and you lose performance. Even the demos of Elm for layout are completely broken.
[0] http://pchiusano.github.io/2014-07-02/css-is-unnecessary.htm...