html, body { width: 100%; height: 100%; }

​

.valign { display: table; width: 100%; height: 100%; }

.valign > div { display: table-cell; width: 100%; height: 100%; }

.valign.bottom > div { vertical-align: bottom; }

.valign.middle > div { vertical-align: middle; }

​

.block { padding: 20px; }

.block.red { background: red; }

.block.yellow { background: yellow; }

.block.green { background: green; }