Works fine in my firefox browser. Has the problem you mention in Google chrome browser. I disabled:
this rule:
display: table-cell;
under:
.home .sf-menu li a
That removed the "jump" issue in Chrome, but obviously messes up the formatting a bit.
Can you achieve the formatting without using "table-cell" ?
Maybe just change
padding: 0 20px;
to
padding: 10px 20px;
in
.home .sf-menu li a