td.accent { text-align: center; font-size: larger; font-weight: bold; background: #eedddd; }
td.instr  { text-align: center; font-size: larger; font-weight: bold; background: #ddddee; }
td.cell  { text-align: center; }
td.zero  { text-align: center; width: 1.5em; height: 1.5ex; background: #eeeeee; }
td.one   { text-align: center; width: 1.5em; height: 1.5ex; background: #bbbbcc; }
td.two   { text-align: center; width: 1.5em; height: 1.5ex; background: #ccccdd; }
td.three { text-align: center; width: 1.5em; height: 1.5ex; background: #ddddee; }
td.four  { text-align: center; width: 1.5em; height: 1.5ex; background: #eeeeff; }