Untitled

<div id="wrapper">

  <div id="header">

    <h1>header</h1>

  </div>

  <div id="left">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Cum aspernatur molestias labore sapiente blanditiis laboriosam nam ut voluptatum qui explicabo officia aliquid est possimus officiis ab pariatur expedita a amet.</div>

  <div id="right">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Fuga molestias nobis ex veritatis error blanditiis neque aliquid aliquam inventore debitis mollitia illum doloremque maiores officia commodi cupiditate amet iusto nisi.</div>

  <div id="footer">Copyright Niels</div>

</div>

* {

  -moz-box-sizing: border-box; 

  -webkit-box-sizing: border-box; 

  box-sizing: border-box;

}

div {

  padding: 10px;

}

#wrapper {

  width: 820px;

  margin: 0 auto;

}

#header {

  float: left;

  width: 800px;

  background-color: orange;

}

#left {

  float: left;

  width: 300px;

  background-color: lightblue;

}

#right {

  float: right;

  background-color: pink;

  width: 500px;

}

#footer {

  width: 800px;

  background-color: yellow;

  clear: both

}