css 가운데 정렬 From http://jsfiddle.net/mBBJM/1/

css_center.css

div{
  background: red;
  bottom: 0;
  height: 100px;
  left: 0;
  margin: auto;
  position: absolute;
  top: 0;
  right: 0;
  width: 100px;
}

/*
http://demosthenes.info/blog/723/Seven-Ways-of-Centering-With-CSS
http://css-tricks.com/quick-css-trick-how-to-center-an-object-exactly-in-the-center/
http://www.paulund.co.uk/absolute-center-images-with-css
http://designshack.net/articles/css/how-to-center-anything-with-css/
*/