/*.page-footer { position:absolute; bottom:0; left:0; right:0; width:100%; height:30px; }*/
.page-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: 30px;
    background: #eee;
    z-index: 99999;
}

@media (max-width: 600px) {
    .page-footer {
        position: fixed;
        bottom: 0;
        left: 0;
        right: 0;
        height: 54px;
        background: #eee;
        z-index: 99999;
    }
}

    .footer-inner {
        padding: 0px 14px;
        display: flex;
        align-items: flex-start;
        justify-content: flex-start;
    }

    .footer-shell {
        position: fixed;
        left: 0;
        right: 0;
        bottom: 0;
        transform: translateY(100%);
        opacity: 0;
        transition: transform 250ms ease-out, opacity 250ms ease-out;
        /* your background, padding, etc. */
    }

        .footer-shell.footer-visible {
            transform: translateY(0);
            opacity: 1;
        }