Ok tnx,
I reduced the width of the menu in vertical position to 130px.
Problem its that there is still too much space between main body and the vertical menu.
http://prntscr.com/cq7zjk
Therefore I tried following code:
.t3-mainbody {
padding-top: 0px!important;
padding-left: 130px!important;
}
Then on large screens main body is getting closer to left. Problem is that padding left still exists on smaller screens (mobile, tablet). If I use the code without "!important" like
.t3-mainbody {
padding-top: 0px!important;
padding-left: 130px;
}
then main body is coming closer to left on small screens but the space on large screen keeps existing though I disabled sidebar1 position.