Trouble with Mystile and smartphone

Hi all, first sorry for my english i’m French user.

So my trouble is : i have custom css for fixed top menu and i meet some error of disposition on smartphone i search on many website a solution but i can’t find. So please help me :).

I put here some codes css i write for custom Mystile Themes :

#top {
position:fixed;
top: 0px auto;
z-index: 1000;
width: 100%;
}

body {
padding-top: 0px auto;
}

#wrapper {
background: #ffffff !important
}

body {
background: #BCBCBC!important;
}

#footer {
background: #BCBCBC;
padding: 0px auto;
}

.footer-wrap {
background: #BCBCBC; !important;
}

#top {
background: #ffffff !important;
}

#top ul.nav > li a:hover {
background: #ffffff;
}

#top {
background: #BCBCBC!important;
}

#header hgroup {
float: none !important;
text-align: center;
}
#header #logo {
float: none;
}

.metaslider {
position: relative;
z-index: 0;
margin:-50px;
}