The majority of desktop and laptop screens nowadays have a width greater than the height. The screen is \"wide\" not \"tall.\" Smart phones have done something rather cool b
Media Queries are probably going to be your solution here for the modern browsers that support it. You can grab a copy of the documentation from here:
http://www.w3.org/TR/css3-mediaqueries/
But you might find the following tutorial useful (Google for: Media Queries Tutorial):
http://webdesignerwall.com/tutorials/css3-media-queries
Once you pick up the basics doing things like hiding elements if the screen falls below a specific resolution:
@media screen and (max-width: 600px)
{
.sidebar
{
display: none;
}
}
Hope this helps.