In my CSS code, the following selectors are highlighted in red "nav, footer, body, header, nav, h1, h2, a, nav a"

/***************
GENERAL
***************/

body {
  font-family: 'Open sans', sans-serif;
}

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

a {
  text-decoration: none;
}



/*********************************
HEADING
*********************************/

#logo {
  text-align: center;
  margin: 0;
}

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; 
 }


    /*********************************
FOOTER
*********************************/

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



  /*********************************
COLORS
*********************************/

/* SITE BODY */
body {
  background-color: #fff;
  color: #999;
}

/* green header */
header  {
  background: #6ab47b;
  border-color: #599a68;
}

/* nav background on mobile devices */
nav {
  background: #599a68;
}

/* logo text */
h1, h2 {
  color: #fff;
}  

/* links */
a {
  color: #6ab47b;
}

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

/* selected nav link */
nav a.selected, nav a:hover {
 color: #32673f;
}