Hi there,
If you'd like to hide the menu, but need to access it later for some reason, you could always attach a display: none;
rule to the site-navigation ID, or main-navigation class in the style.css file.
The rule should look something like
#site-navigation {
css rule;
css rule;
css rule;
}
You can just add the display: none;
rule in with the others and it should cause the menu to disappear entirely, but you can always take the rule out if you need the menu back.
Hope that helps,
Matt