Create an app.css file for our circles (nodes/people) and lines (links/relationships), as follows:
circle {
fill: red;
r: 5;
}
line {
stroke: grey;
stroke-width: 1;
}Don't forget to create a link to it in your index.html file, as follows:
<head>
<link rel="stylesheet" href="app.css">
<script src="https://d3js.org/d3.v5.min.js"></script>
</head>