#main-page .top-padding-click{
    padding-top: 100px;
}

#main-page { 
    background: url(../img/random-number-generator-bg.jpg) no-repeat center center fixed; 
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}