.reveal section .slide-footer {
    position: fixed;
    bottom: 150px;
    width: 100%;
    text-align:center;
    font-size:smaller;
}

/*See https://css-tricks.com/snippets/css/a-guide-to-flexbox/ https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Flexible_Box_Layout/Aligning_Items_in_a_Flex_Container */
.container{
    display: flex;
    justify-content: space-evenly;
}
.col{
    margin: auto;
}
.col-center{
    align-self: center;
}
.col-list{
    align-self: flex-start;
    margin: auto;
}
.container-center{
    display: flex;
    justify-content: center;
}
.container-center-col{
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}
/*https://stackoverflow.com/questions/23082660/how-to-style-images-in-reveal-js */
.reveal section img { background:none; border:none; box-shadow:none; }