I love the democratica theme.  It works great except for a few minor issues.  One of the issues is the left and right sidebar background graphics not extending to the bottom of the page when the right sidebar is longer than the left sidebar and content.  Previously, I fixed this by creating a block in the left sidebar with 50 blank lines.  The following solution is much more elegant.

First edit the bg_left and bg_right png graphics.  Remove most of the white space from the left of the bg_right graphic and the right of the bg_left graphic.  Leave 10 - 15 pixels of white space in each graphic.  The two graphics are 1500 pixels wide and will overlap each other if this is not done.

Now edit page.tpl.php and add two new divisions for the backgrounds directly inside the outer-wrapper division.

<code>
<div id="outer-wrapper">
<div id="background-left">
<div id="background-right">

main content of page, left out because its so long 

</div>
</div>
</div><!-- end #outer-wrapper -->
</code>

Edit layout.css to add the background graphics to our two new divisions.

<code> 
body.layout-both #outer-wrapper #background-left, body.layout-left #outer-wrapper #background-left {
  margin: 0;
  padding: 0;
  background: url(images/bg_left.png) left repeat-y; /* needed for sidebar-left bg color */
}
body.layout-both #outer-wrapper #background-right, body.layout-right #outer-wrapper #background-right {
  margin: 0;
  padding: 0;
  background: url(images/bg_right.png) top right repeat-y;
}   
</code>

The left and right sidebar background graphics now stretch the length of the outer-wrapper when appropriate (if the sidebars are shown).  By shrinking the two background graphics we now have the body background graphic showing through on pages where one of the sidebars are longer than the content.  To fix this add a white background to the outer-wrapper.

<code>
#outer-wrapper {
  width: 94%;
  _width: expression( ( documentElement.clientWidth < 760 ) ? "760px" : "auto" ); /* IE min-width hack */
  min-width: 760px;
  max-width:1200px;
  margin: 10px;
  margin-left: auto;
  margin-right: auto;
  padding: 0;
  background: #fff; /* add this line */
}
</code>

If you have changed the header and footer background graphics the new left and right sidebar backgrounds may be showing through.  To fix this set the header and footer backgrounds to white.  This is only necessary if you have changed the header and footer backgrounds.

<code>
  background: url(images/bg_footer.png) repeat-x top left;
  /* change to */
  background: #fff url(images/bg_footer.png) repeat-x top left;
</code> 

I learned this technique at A List Apart a great website on css.  You can view the article on this at:  http://www.alistapart.com/articles/negativemargins/

Thanks

JJ