@media(min-width: 900px) {
    body {
      width: 900px;
      margin: 0px auto !important;
      box-shadow: black 4px 4px 2px;
      border: 2px solid grey;
    }

    html {
      background: #cfcfff;
      padding: 1em;
      background-image: url("../bgpicture.png");
    }
}
@media(max-width: 900px) {
    body {
      margin: 0px auto !important;
      box-shadow: black 4px 4px 2px;
      border: 2px solid grey;
    }
    html {
      background: #cfcfff;
      padding: 1em;
      background-image: url("../bgpicture.png");
    }
}

div.well {
    display: none;
}