HTML and CSS 3 Column Layout

<div class="col-wrap">
		<div class="main-content">
			<article>
				Text 1
			</article>
			<article>
				Text 2
			</article>
		</div><!-- end main content-->
		<div class="sidebar">
			<article>
				Text 3
			</article>
		</div><!--Close sidebar-->
    </div><!--close col-wrap-->
		<footer>
			<p>These forecasts will be updated every Monday afternoon</p>
		</footer><!--close wrapper-->
	</div>
</body>
</html>

CSS-------------------------------------------------------------------------------------------------------------------------

.main-content{
  width:66%;
  float: left;
  padding: 2%
}
.sidebar{
  width: 26%;
  float: left;
  padding: 2%
}
footer{
  clear: both;
  padding-left:8%;
  padding-bottom:10%;
}
wrapper{
  width:75%;
  margin: auto;
}
img{
  width:45%;
  height:25%;
}
header{
  padding-left:7%;
  padding-right:7%
}
article{
  padding-left:3%;
  padding-right:3%
}
nav{
 padding-left:10%;
 padding-right:10%;
}