#Scaled/Proportional Content with CSS and JavaScript
#https://css-tricks.com/scaled-proportional-blocks-with-css-and-javascript/
Proportional scaling of a *container* is fairly easy
.parent {
height: 0;
padding-bottom: 56.25%; /* 16:9 */
position: relative;
}
.child {
position: absolute;
top: 0; left: 0;
width: 100%; height: 100%;
}