body::before {
    background-size: cover;
    background-attachment: fixed;
    content: '';
    will-change: transform;
    z-index: -1;
    left: 0;
    right: 0;
    bottom: 0;
    top: 0;
    position: fixed;
    background-image: url('../img/bg_main.jpg');
}

footer.mdl-mini-footer {
    padding: 8px 16px;
}
.rt-center-card {
    width: 95%;
    max-width: 768px;
    margin: auto;
    margin-top: 16px;
}

.rt-first-element {
    margin-top: 64px;
}

.rt-bg-light {
    background-color: #eee;
}

#gamewindow {
    display: block;
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    right: 0;
    width: 100vw;
    height: 100vh;
}

.title-image {
    width: 100%;
    height: auto;
}

.rt-fullwidth {
    width: 100%;
    overflow: visible;
}