In the section of "Build Navigation with Unordered Lists." The header does not match.

/****************************
General
*****************************/
body{
  font-family: 'Open Sans' ,sans-serif;
}

a {
  text-decoration: none;
}

img{
  max-width: 100%;
}

#wrapper{
  max-width: 940px;
  margin: 0 auto;
  padding: 0 5%;
}

/****************************
Heading
*****************************/
header { float:left;
  margin: 0 0 30px 0;
  padding: 5px 0 0 0;
  width: 100 %;

}

#logo{
  text-align:center;
  margin: 0;
}
/* anchor color*/
a {
  color:#6ab47b;
}

h1 {
  font-family: 'Changa One', sans-serif;
  margin: 15px 0;
  font-size: 1.75em;
  font-weight: normal;
  line-height: 0.8em;
}

h2{
font-size: 0.75em;
margin: -5px 0 0;
font-weight: normal;
}

/****************************
Navigation
*****************************/

nav{
  text-align: center;
  padding: 10px 0;
  margin: 20px 0 0;
}

/****************************
Navigation
*****************************/

/****************************
Footer
*****************************/

footer {
font-size: 0.75em;
text-align: center;
clear:both;
padding-top: 50px;
color: #ccc;
}

/****************************
Portfolio
*****************************/
#gallery {
  margin:0;
  padding:0;
  list-style:none;
}

#gallery li {
  float: left;
  width: 45%;
  margin: 2.5%;
  background-color: #f5f5f5;
  color: #bdc3c7;
}

#gallery li a {
  display: inline-block;
}

#gallary li, a, p {
  margin: 0;
  padding: 5%;
  font-size: 0.75em;
  color: #bdc3c7;

}



/****************************
Colors
*****************************/

/* green header*/
header { background:#6ab47b;
border-color: #599a68;
}
/* logo text*/
h1, h2 {
  color: #fff;
}
/* nav background on mobile */
nav {
background-color: #599a68;
}

/*  selected nav link color*/
nav a, nav a:visited {
  color: #fff;
}

nav a.selected, nav a:hover{
  color: #32673f;
}
/* site body */
body{
  background-color: #fff;
  color: #999;
}