CSS 3 Hover Effect

CSS Code

body {
  margin: 0px;
  padding: 0px;
  background: #e74c3c;
  font-family: 'Lato', sans-serif;
}
nav {
  float: none;
  clear: both;
  width: 30%;
  margin: 10% auto;
  background: #eee;
}
nav ul {
  list-style: none;
  margin: 0px;
  padding: 0px;
}
nav li {
  float: none;
  width: 100%;
}
nav li a {
  display: block;
  width: 100%;
  padding: 20px;
  border-left: 5px solid;
  position: relative;
  z-index: 2;
  text-decoration: none;
  color: #444;
  box-sizing: border-box;
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
}
nav li a:hover {
  border-bottom: 0px;
  color: #fff;
}
nav li:first-child a {
  border-left: 10px solid #3498db;
}
nav li:nth-child(2) a {
  border-left: 10px solid #ffd071;
}
nav li:nth-child(3) a {
  border-left: 10px solid #f0776c;
}
nav li:last-child a {
  border-left: 10px solid #1abc9c;
}
nav li a:after {
  content: "";
  height: 100%;
  left: 0;
  top: 0;
  width: 0px;
  position: absolute;
  transition: all 0.3s ease 0s;
  -webkit-transition: all 0.3s ease 0s;
  z-index: -1;
}
nav li a:hover:after {
  width: 100%;
}
nav li:first-child a:after {
  background: #3498db;
}
nav li:nth-child(2) a:after {
  background: #ffd071;
}
nav li:nth-child(3) a:after {
  background: #f0776c;
}
nav li:last-child a:after {
  background: #1abc9c;
}
@font-face {
  font-family: 'Lato';
  font-style: normal;
  font-weight: 100;
  src: local('Lato Hairline'), local('Lato-Hairline'),
  url(http://themes.googleusercontent.com/static/fonts/lato/v6/boeCNmOCCh-EWFLSfVffDg.woff) 
  format('woff');
}
@font-face {
  font-family: 'Lato';
  font-style: normal;
  font-weight: 300;
  src: local('Lato Light'), local('Lato-Light'),
  url(http://themes.googleusercontent.com/static/fonts/lato/v6/KT3KS9Aol4WfR6Vas8kNcg.woff) 
  format('woff');
}
@font-face {
  font-family: 'Lato';
  font-style: normal;
  font-weight: 400;
  src: local('Lato Regular'), local('Lato-Regular'),
  url(http://themes.googleusercontent.com/static/fonts/lato/v6/9k-RPmcnxYEPm8CNFsH2gg.woff) 
  format('woff');
}
@font-face {
  font-family: 'Lato';
  font-style: normal;
  font-weight: 700;
  src: local('Lato Bold'), local('Lato-Bold'),
  url(http://themes.googleusercontent.com/static/fonts/lato/v6/wkfQbvfT_02e2IWO3yYueQ.woff) 
  format('woff');
}

HTML Code

<nav>
  <ul>
    <li><a href="">Home</a></li>
    <li><a href="">About</a></li>
    <li><a href="">Work</a></li>
    <li><a href="">Contact</a></li>
  </ul>
</nav>