Resposive Contact Form

<style>
@import url(http://fonts.googleapis.com/css?family=Montserrat:400,700);

html{    background:url(http://thekitemap.com/images/feedback-img.jpg) no-repeat;
  background-size: cover;
  height:100%;
}

#feedback-page{
    text-align:center;
}

#form-main{
    width:100%;
    float:left;
    padding-top:0px;
}

#form-div {
    background-color:rgba(72,72,72,0.4);
    padding-left:35px;
    padding-right:35px;
    padding-top:35px;
    padding-bottom:50px;
    width: 450px;
    float: left;
    left: 50%;
    position: absolute;
  margin-top:30px;
    margin-left: -260px;
  -moz-border-radius: 7px;
  -webkit-border-radius: 7px;
}

.feedback-input {
    color:#3c3c3c;
    font-family: Helvetica, Arial, sans-serif;
  font-weight:500;
    font-size: 18px;
    border-radius: 0;
    line-height: 22px;
    background-color: #fbfbfb;
    padding: 13px 13px 13px 54px;
    margin-bottom: 10px;
    width:100%;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    -ms-box-sizing: border-box;
    box-sizing: border-box;
  border: 3px solid rgba(0,0,0,0);
}

.feedback-input:focus{
    background: #fff;
    box-shadow: 0;
    border: 3px solid #3498db;
    color: #3498db;
    outline: none;
  padding: 13px 13px 13px 54px;
}

.focused{
    color:#30aed6;
    border:#30aed6 solid 3px;
}

/* Icons ---------------------------------- */
#name{
    background-image: url(http://rexkirby.com/kirbyandson/images/name.svg);
    background-size: 30px 30px;
    background-position: 11px 8px;
    background-repeat: no-repeat;
}

#name:focus{
    background-image: url(http://rexkirby.com/kirbyandson/images/name.svg);
    background-size: 30px 30px;
    background-position: 8px 5px;
  background-position: 11px 8px;
    background-repeat: no-repeat;
}

#email{
    background-image: url(http://rexkirby.com/kirbyandson/images/email.svg);
    background-size: 30px 30px;
    background-position: 11px 8px;
    background-repeat: no-repeat;
}

#email:focus{
    background-image: url(http://rexkirby.com/kirbyandson/images/email.svg);
    background-size: 30px 30px;
  background-position: 11px 8px;
    background-repeat: no-repeat;
}

#comment{
    background-image: url(http://rexkirby.com/kirbyandson/images/comment.svg);
    background-size: 30px 30px;
    background-position: 11px 8px;
    background-repeat: no-repeat;
}

textarea {
    width: 100%;
    height: 150px;
    line-height: 150%;
    resize:vertical;
}

input:hover, textarea:hover,
input:focus, textarea:focus {
    background-color:white;
}

#button-blue{
    font-family: 'Montserrat', Arial, Helvetica, sans-serif;
    float:left;
    width: 100%;
    border: #fbfbfb solid 4px;
    cursor:pointer;
    background-color: #3498db;
    color:white;
    font-size:24px;
    padding-top:22px;
    padding-bottom:22px;
    -webkit-transition: all 0.3s;
    -moz-transition: all 0.3s;
    transition: all 0.3s;
  margin-top:-4px;
  font-weight:700;
}

#button-blue:hover{
    background-color: rgba(0,0,0,0);
    color: #0493bd;
}

.submit:hover {
    color: #3498db;
}

.ease {
    width: 0px;
    height: 74px;
    background-color: #fbfbfb;
    -webkit-transition: .3s ease;
    -moz-transition: .3s ease;
    -o-transition: .3s ease;
    -ms-transition: .3s ease;
    transition: .3s ease;
}

.submit:hover .ease{
  width:100%;
  background-color:white;
}

@media only screen and (max-width: 580px) {
    #form-div{
        left: 3%;
        margin-right: 3%;
        width: 88%;
        margin-left: 0;
        padding-left: 3%;
        padding-right: 3%;
    }
}
</style>
<div id="form-main">
  <div id="form-div">
    <form class="form" id="form1">

      <p class="name">
        <input name="name" type="text" class="validate[required,custom[onlyLetter],length[0,100]] feedback-input" placeholder="Name" id="name" />
      </p>

      <p class="email">
        <input name="email" type="text" class="validate[required,custom[email]] feedback-input" id="email" placeholder="Email" />
      </p>

      <p class="text">
        <textarea name="text" class="validate[required,length[6,300]] feedback-input" id="comment" placeholder="Comment"></textarea>
      </p>


      <div class="submit">
        <input type="submit" value="SEND" id="button-blue"/>
        <div class="ease"></div>
      </div>
    </form>
  </div>