need some help with classes

Whenever I try to use classes with css it doesn't work:
<style type="text/css">
a{color: white; text-decoration: none;}
a:hover{color: #c0c0c0;}
th{background-color: #222222;}
.tr1{background-color: #444444;}
.tr2{background-color: #000000;}
</style>

print"<tr class="tr1"><td>".$row[0]."</td></tr>";

All I get is the background color of the page.

i think you need to define them like so:
tr.tr1{background-color: #444444;}
tr.tr2{background-color: #000000;}

but i think you should do the td's rather than the tr's cause.. yah

Your CSS definitions seem fine, it's more likely your browser doesn't support background colors on TR elements. Like notepad said, put them on TDs.

OK thanks alot guys.