I see that originally the height of the main menu background is 190px.
I tried to reduce it to 100px (as below) but the main menu items did not change because of this.
#s5_headerbackground {
width:100%;
height: 100px;
background-attachment: scroll;
background-color: #ffffff;
background-position: center top;
background-repeat: no-repeat;
background-size: cover;}
Any suggestion on how to solve this the best way?