Help making CF7 responsive please

Hi can you help me make my quick homepage contact form responsive please, when i view it ipad or iphone, the form just hangs of the side of the page.

I have customised the form to give it a bit of style, code is as below.

.wpcf7-form{
background: #F7F7F7;
width : 320px;
height: 460px;
overflow: hidden;
margin: 20px;
border: 2px solid #fff;
border-radius: 10px 10px 10px 10px ;
box-shadow: 4px 4px 4px;
}
.wpcf7-form h2{
font-size : 20px;
text-align: center;
}
.wpcf7-form input, .wpcf7-form textarea {
border-color: #808080 #C0C0C0 #C0C0C0 #D4D4D4;
border-style: solid;
border-width: 1px;
border-radius: 10px 10px 10px 10px ;
box-shadow: 4px 4px 5px;
padding: 4px;
line-height: 16px;
font-size: 14px;
width: 250px;
float: none;
margin: 0;
}
.wpcf7-form textarea {
line-height: 16px;
font-size: 14px;
width: 250px;
height: 100px;
}
.wpcf7-form p{
font-size : 14px;
margin-left: 20px;
margin-top: 0px;
margin-bottom: 0px;
width: 250px;
padding: 0 0 10px;
color: #000;
}

Thanks in advance.

http://wordpress.org/plugins/contact-form-7/