HOW TO MARK.(2)

YOU HAVE TO CODE THIS WITH CSS!!!

mark {
  background: cyan;
}

You can change red one if you want.
But remember never change other ones!!!
PLEASE GIVE ME COMMENTS!!!
COMMENT IS VERY HELPFUL FOR ME.

IF YOU DIDN'T WATCH 'HOW TO MARK.(1)'...
http://hahacoding.blogspot.kr/2016/05/how-to-mark1.html