How can I style even and odd elements?

Demo: http://jsfiddle.net/thirtydot/K3TuN/1323/

li {
    color: black;
}
li:nth-child(odd) {
    color: #777;
}
li:nth-child(even) {
    color: blue;
}

<ul>
    <li>ho</li>
    <li>ho</li>
    <li>ho</li>
    <li>ho</li>
    <li>ho</li>
</ul>

Documentation:

• https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-child
• http://caniuse.com/css-sel3 (it works almost everywhere)

The problem with your CSS lies with the syntax of your pseudo-classes.

The even and odd pseudo-classes should be:

li:nth-child(even) {
    color:green;
}

and

li:nth-child(odd) {
    color:red;
}

Demo: http://jsfiddle.net/q76qS/5/

Use this:

li { color:blue; }
li:nth-child(odd) { color:green; }
li:nth-child(even) { color:red; }

See here for info on browser support: http://kimblim.dk/css-tests/selectors/