d3_projection.css

.land {
  fill: #aaa;
}

.county-boundary {
  fill: none;
  stroke: #fff;
  stroke-width: .5px;
}

.state-boundary {
  fill: none;
  stroke: #fff;
}

div.tooltip {
  position: absolute;
  text-align: center;
  padding: 2px 5px;
  width: 255px;
  font: 12px sans-serif;
  background: lightsteelblue;
  border: 0px;
  border-radius: 8px;
  pointer-events: none;
}

.overlay {
  fill: none;
  pointer-events: all;
}