Cloudflare pages not caching CSS or Javascript

I use a free account to serve some minified CSS and Javascipt for my site, uploaded via the pages section.

The CSS and JS assets on my own site observe my expires headers, but the Cloudflare ones have max-age=0 and must-revalidate headers, resulting in very poor performance.

I’m using Apache, with my virtual host expires settings as follows:

ExpiresActive On
ExpiresDefault A0
ExpiresByType text/css A2592000
ExpiresByType text/javascript A2592000

Why is this happening, and how do I force Cloudflare to cache?

Maybe I’ve set it up completely wrong. I’m not trying to host an entire site at Cloudflare, just a couple of CSS and JS files. I put them in the “Page” section, but perhaps that’s not correct. I don’t want to add my site to Cloudflare, so how do I do this and get the caching to work properly?