.talk-slides {
    background: url('../images/loading.gif') center no-repeat;
    min-height: 275px;
}

@screen md {
    .talk-slides { min-height: 375px; }
}

@screen lg {
    .talk-slides { min-height: 450px; }
}

@screen xl {
    .talk-slides { min-height: 560px; }
}