Say you wanted to have a fixed width layout website, and the content floated in the middle of the screen. You can use the following CSS command:
#content
{
width: 700px;
margin: 0 auto;
}
You would then enclose body { text-align: center; } #content { text-align: left; width: 700px; margin: 0 auto; } This will then centre align the main content, but it'll also centre align the text! To offset the second, probably undesired, effect we inserted text-align: left into the content div.