This is my site . On the home page 3 the box I put class = "list_home". Happened to me is a problem when users zoom in site! Moving box look so bad! I need help. thank you everyone

This is my CSS
HTML Code:
-moz-transition: all 0.7s ease 0s;
    background: none repeat scroll 0 0 #ECECEC;
    border: 2px solid #DBDBDB;
    display: block;
    float: left;
    margin-left: 13px;
    margin-right: 12px;
    min-height: 305px;
    padding: 10px 29px 10px 10px;
    width: 28%;