@import url(http://fonts.googleapis.com/css?family=Open+Sans:400,300);

body {
  margin: 0; padding: 0;

  font-family: "Open Sans";
  font-size: 15px;
  line-height: 24px;
  font-weight: 400;

  background-color: #ecf0f1;

  -webkit-text-size-adjust: 100%;
}

h1 { font-weight: 300; }
h2 { font-weight: 300; }
h3 { font-weight: 300; }
h4 { font-weight: 300; }

img { max-width: 100%; }
@import url(http://fonts.googleapis.com/css?family=Open+Sans:400,300);

body {
  margin: 0; padding: 0;

  font-family: "Open Sans";
  font-size: 15px;
  line-height: 24px;
  font-weight: 400;

  background-color: #FFF;

  -webkit-text-size-adjust: 100%;
}

h1 { font-weight: 300; }
h2 { font-weight: 300; }
h3 { font-weight: 300; }
h4 { font-weight: 300; }

img { max-width: 100%; }

#content article {
  padding: 0 5%;
  max-width: 800px;
}
Add content padding and reset body background.
Add content padding and reset body background.