cljfx/css is pretty dumb (or simple, of you wish), it only converts maps to indented curly-braced blocks. {"@font-face" {:src ...}} should do the trick

The only issue here is that it seems valid to specify multiple font-face rules. I wonder if extending the syntax to accept a vector value and just repeating the key for each might be a simple solution?

ah, that's a good point

please file an issue!