Height proportional to width using padding % and absolute position

ori: http://jsfiddle.net/Matt_Coughlin/agtyt/3/ ref https://stackoverflow.com/a/18164974

by Roberto Apasajja

HTML

<div class="content">
    Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum.
</div>

<br/>

<div class="wrapper">
    <div class="content2">
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat.
    </div>
</div>

CSS

.content {
    width: 100%;
    height: 0;
    padding-bottom: 30%;
    background-color: #7ad;
}
.wrapper {
    position: relative;
    width: 100%;
    padding-bottom: 30%;
    background-color: #7ad;
}
.wrapper .content2 {
    position: absolute;
    width: 100%;
    height: 100%;
    background-color: #7da;
}