CSS does not work for Firefox

I have a css file and one of the classes is as follows:

.thumnail { 
    padding-left:100px;
    padding-top:20px;
}

When i refer to the class thumnail for a table <tr> in Internet Explorer it works and in Firefox it does not. Can any one hel开发者_Go百科p me out please?

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From the specification for padding:

Applies to: all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column

A <tr> element is, by default, display: table-row so padding should not have any effect on it.

If you want to adjust the space between <td> and <th> elements, you need to use the border-spacing property (and apply it to the <table> element).