timhunt/moodle-qtype_ddmarker — comment on commit 16d3c3329e722325b580b0abe3abeae764255bc2
File:  line 0
By timhunt:

For me, I was getting form validation errors with any whitespace in the coordinate strings, which annoyed me. Clearly my approach is the wrong way to fix it.

I made an image, and I planned to commit both the png and the original Gimp file, for future editing. Clearly I failed.

That CSS syntax is explained on http://docs.moodle.org/dev/Themes_2.0_How_to_use_images_within_your_theme#Using_images_within_CSS (which I just edited to make it clearer).