Ts2102

found a solution for the problem. Go to >theme > theme options > layout > and then place this in custom css.

@media screen and (max-width: 480px) {

 #header {
  position: relative;
  padding-bottom: 30px;
 }

 #access {
  background: none;
 }

 #access,
 #access .nav-show,
 #access a.nav-show:hover {
  bottom: 0;
 }

 #access .nav-show,
 #access a.nav-show:hover {
  top: initial;
  left: 44%;
 }

 #access:target .menu {
  margin-top: 0;
 }

}

i got the same problem. http://nefertariappingedam.nl/ when watched on mobile device the menu goes over the logo.