nvd3/src/css/forceDirectedGraph.css

A reusable charting library written in d3.js

.nv-force-node {
    stroke: #fff;
    stroke-width: 1.5px;
}

.nv-force-link {
    stroke: #999;
    stroke-opacity: .6;
}

.nv-force-node text {
    stroke-width: 0px;
}