Ahoj Vaclav,

please use below Custom CSS in custom.css file, first add that:

.rv-mod-menu-right .nav.menu {display: block;}

and customize that class name into that new one (current line 65):

.rv-mod-menu-right .nav > li a {
  color: #EAEAEA;
  border-style: solid;
  width: 100%;
  display: block;
  padding: 5px;
}

after using it