I changed value of "border-bottom" and "margin-bottom", but it just had no difference.
(I think if i give some change to the value, the full screen on the right will react. right?)
So, why I can't get know the border-bottm and margin-bottom
Yes, that's right, it will.
You have commas between the values in the border-bottom, that might be blocking the changes.
You are missing one } in that file. Can you spot where? The will be blocking the changes as well.