path { 
    stroke: steelblue;
    stroke-width: 1;
    fill: none;
}
.axis path,
.axis line {
    fill: none;
    stroke: grey;
    stroke-width: 1;
    shape-rendering: crispEdges;
}

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

.focus circle {
  fill: none;
  stroke: SeaGreen;
}