Header size smaller

I changed this line

header {position:relative; width:100%; text-align:center; display:block; margin-bottom:90px; padding:8% 0 6% 0; background-size:cover; background-position:center;}

to

header {position:relative; width:100%; text-align:center; display:block; margin-bottom:90px; padding:2% 0 2% 0; background-size:; background-position:center;}

When i do this in f12 of page I get the desired result , but when I apply this in editor it doesnt change a thing