Maximize Content Area

Hi,

i want to enlarge the content area from Twenty Eleven and i tried this, but nothing happened:

#content {
margin: 0 0% 0 0%;
width: 100%;
}

#secondary {
float: right;
margin-right: 0%;
width: 0%;
}

I already eliminated the margins and paddings:

html, body

#page {
margin: 0em 0em;
max-width: 2000px !important;
}

body {
padding: 0 0em;
}

I even tried all with the “!Important” command.
Sorry I cannot give you a link

Thanks fpr your support