body {
              font: 10px sans-serif;
            }

            .axis path,
            .axis line {
              fill: none;
              stroke: #000;
              shape-rendering: crispEdges;
            }



            .line {
              fill: none;
              stroke-width: 5px;
            }
        
           /*ugly way before I found Mike Bostock's example
             .points {opacity: 0;}
            .points:hover {opacity: 1;}*/

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