Phase 2 CSS changes
Convert almost all pixel dimensions to % or em. In general, use em where the value will be impacted by different font sizes. Use % for big page dimensions or other major dimensions on the page. (Generally I use percent for widths of containers.)

Images for div img and main img are enhanced by fluid dimensions:
width: 100%;
max-width: 100%;

This allows the image to display at 100% of its width and no wider. This prevents the image from leaving its container, overlapping with other images, etc. This scales the HTML dimensions of the image — it does NOT reduce file size of the image for smaller dimensions. This is NOT “responsive images”, which we cover later. This is a little hack that will make images behave for the moment while we style around them.

html {
  box-sizing: border-box;
}
*, *:before, *:after {
  box-sizing: inherit;
}
body {
	font-family: Arial, Geneva, sans-serif;
	background-color: #B1D3EE;
	font-size: 100%;
}
h1,h2,h3,h4,h5,h6 {
	font-family: 'Cabin Condensed', sans-serif;
}
a {
	color: #2772B0;
}
.wrapper {
	width: 97%;
	max-width: 1200px;
	margin: 0 auto;
	float: none;
	background-color: #fff;
}
header {
	background: url(../img/boston-1200.jpg) no-repeat;
	width: 100%;
	height: 218px;
	font-family: 'Cabin Condensed', sans-serif; 
	color: #fff;
}
header h1 {
	padding: 0.5em;
	margin: 0;
}
header h1 a{
	color: #fff;
	text-decoration: none;
}
nav {
	background-color: #ED8F00;
}
nav ul {
	margin: 0;
	padding: 0;
	list-style-type: none;
	overflow: auto;
}
nav ul li {
	font-family: 'Cabin Condensed', sans-serif;
}
nav ul a {
	color: #fff;
	text-decoration: none;
	font-weight: bold;
	padding: 1em;
	float: left;
}
nav ul a:hover {
	color: #a16100;
}
main {
	overflow: auto;
	padding-right: 3em;
	background-color: #EFECCA;
}
main h2 {
	font-size: 3em;
	padding-top: 1em;
}
main p {
	font-size: 1.5em;
	font-family: 'Cabin Condensed', sans-serif;
}
div {
	float: left;
	width: 20.5%;
	margin-left: 2.5em;
}
div img {
	width: 100%;
	max-width: 100%;
}
main img {
	float: left;
	margin-right: 1.875em;
	width: 100%;
	max-width: 400px;
}
footer {
	clear: both;
	padding: 2em 0;
	margin: 3em 0;
	color: #999;
	text-align: center;
}