elm-ui: Forget CSS and enjoy creating UIs in pure Elm

Creating UIs with CSS is rarely as straightforward as you expect.

A few weeks ago I wanted to make the navigation on my site responsive, having it switch from a row of links to a hamburger slideout menu. Seems like a reasonable thing to do with CSS, right?

Not really. As often happens, I tried a few reasonable things -- they didn't work. I started searching for solutions -- most involved JavaScript.

I finally found a solution that was CSS-only, and then spent a couple of hours trying differe...