Tuesday Lobsang Rampa 
This Earth is just a speck of dust existing for the twinkle of an eye in what is real time
~ ~ ~
By nature, the background color on any div will only show for the length of the content. This means if you're using a background color or border to create the look of a side column, it won't extend all the way to the footer but will stop when the content ends. If the .content div will always contain more content, you can place a border on the .content div to divide it from the column.