Pixel-less layouts using em and %  In a time when the pixel
density of mobile phones is no longer comparable to normal
computer screens and laptops are going the same way, using
pixels to set the dimensions of your website makes less sense
than it used to. So let's build an alternative setup.  The other
units  There are at least two other units that are useful for
layout, em and %. 1em is equal to the current font-size and %
means percentage of the surrounding element.  Percentage is a
good second in popularity behind pixels, and em is not commonly
used for other things than font sizes. But since em is not px,
it has other advantages.  A simple web page  Our simple web page
consists of some space at the top a for a logo and slogan etc.,
a horizontal menu, main content area, a sidebar and a footer. A
simple sketch might look like this  Webpage layout sketch  So
let's explore some options for building this with em and %. The
first thing to do is to set up some basic html code for our page
<div id="top">         <div