This shows the codes and standards:-
but if you can understand it you're better than I am.
I don't use CSS tables because I think older browsers won't process them.
The height of a 'table-row' element's box is calculated once the user agent has all the cells in the row available: it is the maximum of the row's specified 'height' and the minimum height (MIN) required by the cells. A 'height' value of 'auto' for a 'table-row' means the row height used for layout is MIN. MIN depends on cell box heights and cell box alignment (much like the calculation of a line box height). CSS 2.1 does not define how the height of table cells and table rows is calculated when their height is specified using percentage values. CSS 2.1 does not define the meaning of 'height' on row groups.
In CSS 2.1, the height of a cell box is the maximum of the table cell's 'height' property and the minimum height required by the content (MIN). A value of 'auto' for 'height' implies that the value MIN will be used for layout.
CSS 2.1 does not specify how cells that span more than one row affect row height calculations except that the sum of the row heights involved must be great enough to encompass the cell spanning the rows.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.