+td.di-b {background: #F77} /* bmp */
+td.di-b:hover { color: #F77; background: #000}
+td.di-d {background: #FF6} /* rfc-1345 digraph */
+td.di-d:hover { color: #FF6; background: #000}
+td.di-prop {background: #FC6} /* proposed digraph */
+td.di-prop:hover { color: #FC6; background: #000}
+td.di-a {background: #CF8} /* ascii */
+td.di-a:hover { color: #CF8; background: #000}
+td.di-aa {background: #8F8}
+td.di-aa:hover { color: #8F8; background: #000}
+
+td.Co {background: #DBB} /* private */
+td.c-na,