/* Minimum height we need is 420 (height of login form plus heights of nav and footer) */
@media all and (max-height: 420px){
    footer {
        visibility: hidden;
        opacity: 0;
        transition: visibility 1s, opacity 0.5s linear;
        /*display: none;*/
    }
}

@media all and (min-height: 420px){
    footer {
        visibility: visible;
        opacity: 1;
        transition: visibility 1s, opacity 0.5s linear;
        /*display: none;*/
    }
}

footer {
    border-top: 1px solid #337ab7;
    bottom: 0;
    position: absolute;
    width: 100%;
    text-align: center;
    padding: 10px;
}