Finishing: Web page technology CSS Page Layout center problem

css| Page | question 1, div center body {Text-align:center}
div {margin-right:auto; margin-left:auto;}
Description

For IE, the parent element defines "text-align:center;" It's okay.

For other browsers, such as FF, only this is not centered, you need to define "Margin-right:auto" in the child elements; Margin-left:auto; ".

2, the background center body {background:url (#) #fff No-repeat Center;
Description: Center in the argument is the definition of the background position.

3, the text vertically centered
div {vertical-align:middle;line-height:? px;} Description

Vertical-align:middle indicates that the row is centered vertically, we adjust the line spacing to be as high as the entire Div, and the text is centered vertically.