The TwentyTen sidebar is, by default, 220 pixels wide.
This, for many, is going to be a problem, because it makes it impossible to place two 125×125 adverts or banners next to each other.
The obvious way to solve this is to widen the sidebar. The width is defined in the STYLE.CSS file in the theme directory, which can be edited in WordPress administration panel.
The trouble is that you have to change not just one but three values. For my example, I shall widen the sidebar by 100 pixels:
1. Log into WordPress using an administrator account.
2. Now click on “Editor” in the “Appearance” section of the sidebar.
3. Next, click on “Stylesheet (style.css)” on the right-hand side of the screen.
4. Scroll down to the area labelled “LAYOUT: Two columns”.
5. Here are the three values that we need to change:
6. Subtract 100 from the second value on the “margin” line in the “#container” element:
7. Add 100 to the second value on the “margin” line in the “#content” element:
8. Add 100 to the width value in the “#primary, #secondary” element:
9. Now save the changes, and the sidebar should now be wider and the content narrower:
Of course, you can replace the 100 with a different number to suite your own design needs.