The topic you linked to was actually for a different theme, Franz Josef. Though Graphene and Franz Josef share similar layout framework (Bootstrap), the way they’re implemented is quite different. You will likely need different code for Graphene.
To move the position of the header bar over the header and set it’s background to transparent, you can use this code:
.navbar {
margin-top: -40px;
background: none;
}
.navbar-inverse #header-menu-wrap {
background: none;
}