Uneven column widths

make sure you have content in the blocks that you're resizing. sometimes if there is no content in the sidebar first for example, the css changes may not appear to have taken effect.

make sure you change all/the right values for the sidebar first/last declaration. they appear several times depending on the number of columns you plan to use.

if this is a fixed width site, make sure your numbers add up. if you take 20px off of sidebar last, make sure it's added back somewhere else.

clear you cache then reload the page

OK, so here's what you'll need to do: First, the section you'll edit will be the Columns section. Open your style.css and scroll down till you see

/****************************************/
/* COLUMN LAYOUTS /
/ /
/ Classes for different column layouts /
/ that are applied to the tag. */
/****************************************/

This is where you'll need to make your mods. Before you change anything, you need to determine which style you're using, Single, Two or Three column. From your post, I'm assuming, of course, that you're using a 3 column layout. So you'll need to scroll down a bit further till you reach the 3 column layout:

/**********************************/
/* THREE COLUMN LAYOUT /
/ (Sidebar:Main Content:Sidebar) */
/**********************************/

This is the exact area to edit for your layout. It can get a bit tricky and will be a little time consuming... but nothing horrible. The main thing you'll need to do is keep your width sizes within the outer wrapper. When you increase one side, you'll not only need to edit the other, but you may very well need to adjust the content inner (main content) area as well to prevent vertical shifting due to the widths pushing the sidebars out of the wrapper and to keep things looking uniform and "right". I can't tell you what values to enter, of course, but I can tell you that you'll surely need to edit the margins too. Here's a little example; this is EXACTLY where you'll need to edit:

body.layout-first-main-last #sidebar-first { <---------------Controls your first (left) sidebar size & position---
margin: 40px 20px 0 0; /* LTR */
width: 240px;
}

body.layout-first-main-last #content-wrapper { <---------------Controls your main content region size & position---
margin: 40px 0 0;
width: 700px;
}

body.layout-first-main-last #content-wrapper #content-inner {
}

body.layout-first-main-last #content-wrapper #sidebar-last { <----------------Controls your last (right) sidebar---
background-color: #F4F7E7;
margin: 0;
padding: 0 0 0 20px; /* LTR */
width: 280px;
}

That's it! Just play around with these areas until you get the look your client desires. Make sure you drop a copy of the css on your pc before any changes (in case you need to start over). By default, the areas fit together tightly, so as soon as you make a change to one sidebar, you'll probably see the others get "out of whack". Don't worry... just continue to make the changes and as long as you keep everything evened-out, it'll come out fine. Ask away if you need more help.

Good luck!

Chris