Found these commented out in an old project – not tested again to see if they are still valid.
/* Full width fluid sidebar-Main-sidebar */
.custom .full_width .page {width: auto;}
.custom .full_width #column_wrap {width: 75%; margin: 0 25% 0 0;background: transparent url(images/dot-004000.gif) repeat-y scroll 20% 0;}
.custom .full_width #content {width: 80%; margin: 0 0 0 20%;float:left;}
.custom .full_width #sidebar_1 {width: 20%; margin: 0 0 0 -100%;}
.custom .full_width #sidebars {width: 25%; margin: 0 0 0 -25%;}
.custom .full_width #sidebar_2 {width: auto;}
.custom .teasers_box {width: 100%;margin: 0;}
.custom .teaser {width: 50%;}
.custom .teaser h2 {margin: 0 0.9em;}
.custom .teaser .teaser_date {margin: 0 1.5em;}
.custom .teaser .format_teaser {margin: 0 1.2em;}
.custom .teaser .teaser_link {margin: 1em 1.5em;}
.custom .no_sidebars {background: #FFF !important;}
.custom .no_sidebars #content {margin: 0;}
/* Full width fluid sidebar-Main */
.custom .full_width .page {width: auto;}
.custom .full_width #content {width: 80%;}
.custom .full_width #sidebars {width: 20%;}
.custom .teasers_box {width: 100%;margin: 0;}
.custom .teaser {width: 50%;}
.custom .teaser h2 {margin: 0 0.9em;}
.custom .teaser .teaser_date {margin: 0 1.5em;}
.custom .teaser .format_teaser {margin: 0 1.2em;}
.custom .teaser .teaser_link {margin: 1em 1.5em;}
.custom .no_sidebars {background: #FFF !important;}
.custom .no_sidebars #content {margin: 0;}