validate_event.html: nicer styles
validate_event.html: nicer styles

Now we have a better indication if there are errors in the event URL
file or not.

pbanaszkiewicz/amy,wking/swc-amy,pbanaszkiewicz/amy,vahtras/amy,vahtras/amy,shapiromatron/amy,shapiromatron/amy,wking/swc-amy,shapiromatron/amy,pbanaszkiewicz/amy,swcarpentry/amy,swcarpentry/amy,swcarpentry/amy,vahtras/amy,wking/swc-amy,wking/swc-amy