message: white for negative values
diff: return function getColor(value, property) {
  property = property || 'background-color';
  var color = 0;
  - if (value <= 85) {
  + if (value < 0) {
  + return 'white';
  + } else if (value <= 85) {
  color = 0;
  } else if (value <= 90) {
  color = 20;
  color = 120;
  } else if (value >= 100) {
  color = 190;
  - } else {
  - return 'white';
  }
  var result = {};
  result[property] = 'hsl(' + color + ',85%,60%)';
  