Add your theme to the public Fluxer World gallery. Fill the form, hit Submit — it goes live immediately.
The easiest way to get the CSS: open Fluxer's settings → Appearance, customise your theme, click Export as CSS, then paste the contents below. Or use the Load current theme into editor button inside the CSS overrides box.
My themes
Edit metadata or delete themes you've published. Changing the CSS = publish a new theme (the id is derived from the CSS body).