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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Elements3</title>
</head>

<body>
<ul>
  <li>Hello, This is first element</li>
  <li>Whidy! so many elements</li>
  <li>Whidy! so many elements</li>
  <li>Whidy! so many elements</li>
  <li>Here it is, The last element</li>
</ul>
</body>
</html>
ul {
    border: 1px solid #000;
    margin: 0;
    padding: 0;
    list-style: none;
    float:left;
}
ul li {
    background:#eee;
    color: #F00;
    margin: 50px;
}
ul li:nth-child(2n) {
    color: #000;
    margin-top: 0 !important;
    margin-left: 0 !important;
}