Christmas Bird Count history report system

Spacer cells are gray so they are distinct from number cells with not much content.

td.sp
{ background: #aaaaaa;  /* Middle gray */
  border: 1px black solid;
}

The original version of this rule lacked the border: declaration. This caused a subtle bug: if a spacer cell occurred in the top physical row (as would be the case with 9 logical columns in 10 physical columns, when an extra physical row is added to accommodate the suffix cells), its top border was not thickened.

The problem was that although the td.c1 rule specified a thick border, that rule did not specify a style or color. Because the default style is none, specifying the width was not sufficient. The fix was to add a thin black solid border on all sides in this rule, so that when modified by td.c1 the top border will be heavy, black and solid.