flipside-js/src/spectrum/plot/style.css

.light .marker {
  fill: #2d57ed;
}
.light .line {
  stroke: #2d57ed;
}
.light .related {
  fill: #000;
}
.light .relatedLine {
  stroke: #000;
}

.dark .marker {
  fill: #20b7fc;
}
.dark .line {
  stroke: #20b7fc;
}
.dark .related {
  fill: #fff;
}
.dark .relatedLine {
  stroke: #fff;
}

.marker {
  font-size: 12px;
}

.line {
  stroke-width: 1;
}

.relatedLine {
  stroke-width: 0.5;
}

.legend {
  font-size: 7px;
}