body {
    -webkit-transition: background-color 1s;
    transition: background-color 1s;
}
html, body { max-height: 100%; }
body.loading {
    background: #fefdfd url(../../resources/img/loading.gif) no-repeat 50% 50%;
    background-size: 300px;
    -webkit-transition: background-color 0;
    transition: background-color 0;
    opacity: 0;
    -webkit-transition: opacity 0;
    transition: opacity 0;
}