In your CSS class .box is margin-top:30px or height:100%. This is what makes white space at the bottom of your website
box {
background: #fff none repeat scroll 0 0;
box-sizing: border-box;
height: 100%; **//Set it to "auto"
margin-top: 30px; **//or this one, change it to 0px or remove**
overflow: hidden;
width: 100%;
}