I have code like this :

```
    /*footer*/
footer{
  position:relative;
  display:block;
  padding:15px;
  text-align:center;
  background:#000;
  margin:0 169px;
}

    /*Footer*/
@media only screen and (min-width:600px){
  #footer-wrapper .footer{
     float:left;
     width:100%;
     display:block; 
     margin:0 auto
  }
}

@media only screen and (min-width:768px){
  #footer-wrapper .footer{
    width:100%; 
    margin:0 auto
  }
}

@media only screen and (min-width:992px){
  #footer-wrapper .footer{
    width:100%; 
    margin:0 auto
  }
}

```

in desktop, i have margin right and left 169px. but in mobile i have margin right and left 169px too. I want remove that margin on mobile version. But my @media screen doesn't work