Yeah, computers and browsers can act funny at odd times.

I'm thinking maybe your occurrence was because of temporary files harvested from the browser while adjusting the colors in the stylesheet. Sometimes, you have to flush the temp files for the browser to react. Especially when overwriting image files, I know Firefox takes a bit to acknowledge the new file.

Yesterday, my "Enter" key stopped working into the wee hours here in the forum. I had to type out responses on Notepad to obtain paragraph breaks and then copy/paste them into the forum input box. Of course, all is well today.