HELP CSS code in style sheet for CSS Positioning No 7 Exercise 6 is missing

Hey, so I completed half of this model, CSS positionong no 7 (Learn HTML and CSS: part I) also called exercise no 11 in the forums(?), but is exercise 6 of Model 7, and well I took a break, shut it down. Now I turned it back on and all the CSS code in the stylesheet is missing!!?

Is there a system malfunction?

Could someone find me the CSS code so i could copy and paste it into my stylesheet? I need it to finish this model.

it appears that even if i restart exercise no 1 in that model, the CSS code is gone and I know it was there in the start of the exercise this morning.

What to do?