php - Bootstrap Form Is Not Responsive In Mobile -

i've created landing page looks fine on desktop, horrible in mobile. form goes outside of background image , creates lot of white space. there way make form stay inside of background image?

thanks!

here link , code snippet: crimsonroot.com/files/php/gettr.php

<div class="col-md-6 col-md-offset-3 col-sm-6 col-sm-offset-3 col-xs-12 center">                  <form>                  <div class="form-group">                      <input type="text" class="form-control" name="name" id="name" placeholder="name"/>                  </div>                  <div class="form-group">                      <input type="email" class="form-control" name="email" id="email" placeholder="email"/>                  </div>                  <button id="gogettr" class="btn btn-success btn-lg">make me go gettr!</button>              </form>  </div> 

modify .container class this:

.container { background-attachment: fixed; /* modified here */ background-image: url("gettrbackground.jpeg"); background-position: center center; background-size: cover; min-height: 100%; /* modified here */ padding-top: 100px; width: 100%; }