table.oper {
  margin: 1em 1.5em 1em;
}

table.oper td {
  border: solid 1px #006;
  padding: 0.5ex;
}

td.op, tt {
  white-space: nowrap;
  font-family: monospace;
}

img.ill {
  float: right;
  margin: 1ex;
  border: solid 1px #006;
}