html,body {
    height: 100%;
}
.image-background {
    background-image:url('/img/bg_summer.jpg');
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center center;
}
.transparent-sign-in {
    background: rgba(128,128,128,0.5);
}
.transparent-sign-in a, .transparent-sign-in label, .transparent-sign-in legend, .transparent-sign-in p {
    color: #fff !important;
}
.transparent-sign-in p {
    text-align: center;
    font-size: 12px;
}