<div id="form">
      @using (Html.BeginForm("Foo", "Boo", FormMethod.Post, new { @class = "form-horizontal" }))
      {
           //form here
      }
</div>

<!-- container-->
<div class="main-content">
    <div class="container">
        @RenderBody()
    </div>
</div>
<!-- /container -->

.main-content {
    padding: 20px;
    margin: 0;
    width: 100%;
}

.container {
    margin: 0 auto;
    width: 100%;
}

#form {
    margin: 0 auto;
}

.form-horizontal {
    max-width: 700px;
    width: 100%;
    background-color: #ffffff;
    font: bold 14px sans-serif;
    margin: 0 auto;
    border-width: 150px;
    border-style: solid;
    border-image: url(../../images/Iphone.png) 25%;
}