.tab{
border:1px solid #cad9ea;
color:#666;
}

.tab th {
background-image: url(th_bg1.gif);
background-repeat::repeat-x;
height:30px;
}

.tab td,.tab th{
border:1px solid #cad9ea;
padding:0 1em 0;
}

.tab tr:nth-of-type(odd){ background:#f5fafe;}//奇数行
.tab tr:nth-of-type(even){ background:#ffffff;}//偶数行
.tab tr:hover{background-color: #e8f3fd;}//鼠标经过变色