I've replaced it with nth-child
tr.odd {
background-color: #ddd;
}
tr.even ...

I've replaced it with nth-child
tr.odd {
background-color: #ddd;
}
tr.even {
background-color: #fff;
}

with

tr:nth-child(odd) {
background-color: #ddd;
}
tr:nth-child(even){
background-color: #fff;
}

Also, as per #14 there are no pseudo classes as :odd & :even for now.