FlexBox

Just amazing way to have a better layout in webapps.

Here a small tutorial on nettuts.

http://net.tutsplus.com/tutorials/html-css-techniques/an-introduction-to-css-flexbox/

 

Cover

background-size: cover allows to use a image as a background que expands all the way the html element (stretching or expanding as needed)

 

Border-Images

Border images seems to nine-patch png on android or flash, allowing an image to stretching and expanding only inside some region => great to create buttons right from psd