You can set width on the body

by nwellcome

HTML

<html>
    <head>
    </head>
    <body>
        <p>Some html text</p>
    </body>
</html>

CSS

html {  
 text-align: center;
 background-color: #99e;
}

body {
    width: 260px;
    margin: 0 auto;
    background-color: #e99;
    text-align: left;
}