The background color on this div will only show for the length of the content. If you'd like a dividing line instead, place a border on the left side of the #mainContent div if the #mainContent div will always contain more content than the #sidebar1 div.
Donec eu mi sed turpis feugiat feugiat. Integer turpis arcu, pellentesque eget, cursus et, fermentum ut, sapien.
Sidebar2
The background color on this div will only show for the length of the content. If you'd like a dividing line instead, place a border on the right side of the #mainContent div if the #mainContent div will always contain more content than the #sidebar2 div.
Donec eu mi sed turpis feugiat feugiat. Integer turpis arcu, pellentesque eget, cursus et, fermentum ut, sapien.