Center Mobile Menu Changes Menu on Desktop

Hi,

I was wondering if anyone could help me.

my website is: http://www.diegoplaysdrums.com

Based on other forums I was able to center my menu on mobile but it cause the menu on the desktop to turn white.

Heres the CSS i used.

#header #searchform {
display: none;
}

#social-media-icons {
margin-right: 2%;
}

#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;
}

#access,
#social-media-icons {
position: relative;
}

#access .nav-show,
#access a.nav-show:hover {
bottom: -38px;
}

Can anyone help me?