<div class="container">
  <header>
    <h1 class="main-header">Interwebz</h1>
    <nav>
      <a class="nav-item" href="#">Tracks</a>
      <a class="nav-item" href="#">About</a>
      <a class="nav-item" href="#">Blog</a>
      <a class="nav-item" id="interwebz" href="#">InterWebz Here</a>
    </nav>
  </header>
</div>
/* Universal Selector, least specific */
* {
  font-size: 16px;
}
/* Element Selector, will override Universal */
a {
  text-decoration: none;
}
/* Class Selector, will override Universal and Element Selectors */
.main-header {
  font-size: 24px;
  color: gold;
}

.nav-item {
  padding: 5px 20px;
  background: lightgray;
  border: 1px solid gray;
  margin: 10px;
  border-radius: 5px;
  display: inline-block;
  color: black;
}

/* Pseudo-Class Selector */
.nav-item:hover {
  background: #e3e3e3;
}

/* ID Selector, will override Class, Element and Universal */

#interwebz {
  background: gold; /* adding !important will force this to be used rather than the last item on the list */;
}
/* Cascading Styles, this overrides the above ID Selector */
#interwebz {
  background: green;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.