The panels module is the ideological son, successor to and almost complete replacement for the dashboard module. This module allows you to create pages that are divided into areas of the page. Where the dashboard module only gave four areas--top, bottom, left and right--this one is a completely flexible system that includes a couple of 2 column and 3 column layouts by default, but is also highly extensible and other layouts can be plugged in with a little HTML and CSS knowledge, with just enough PHP knowledge to be able to edit an include file without breaking it. Perhaps most importantly, unlike the dashboard module it requires no fiddling with PHP code to include the things you want; the interface lets you add blocks, nodes and custom content just by selecting and clicking. If you want to override the CSS of a panel, the easiest way is to just copy the CSS into your theme directory and tweak; panels will look there before including the CSS from the module, and if it exists, will not include the module's CSS. If you want to just change a tiny bit but keep the basic structure, just add your changes to your style.css instead. If you're having problems with IE and your panels falling below your sidebars, try setting the width of the main panel area (example, .panel-2col-stacked) to 98%. If you need to check if the current page is a panels page in your theme (for example if you want to hide some existing sidebars in your theme on these pages) then you can use the panels_is_panels_page() function.