Pretty hover effect (D3 chart) - css

Question

Alright, I'm trying to emulate the CSS effect on this chart:
http://bl.ocks.org/bobmonteverde/2070069
When you hover over a point, it creates a bigger circle around the point.
For the life of me, I can't figure out what I'm missing in my own CSS :)
my Fiddle: https://jsfiddle.net/y3LpjLph/3/
CSS:
/* Line Chart CSS */
.axis path,
.axis line {
fill: none;
stroke: #000;
stroke-width: 3px;
shape-rendering: crispEdges;
}
#pipeline-1,
#pipeline-2 {
fill: none;
stroke-width: 1.5px;
stroke-linecap: round;
transition: stroke-width 250ms linear;
-moz-transition: stroke-width 250ms linear;
-webkit-transition: stroke-width 250ms linear;
transition-delay: 250ms
-moz-transition-delay: 250ms;
-webkit-transition-delay: 250ms;
}
.x.axis path {
/* Uncomment below if I want to remove x-axis line */
/* display: none;*/
}
stroke-opacity: 0;
fill-opacity: 0;
#pipeline-chart-render {
padding-left: -50px;
}
.area {
fill: gray;
opacity: 0.2;
}
.legend-items text {
fill: steelblue;
}
.legend {
fill: white;
text-decoration-color: blue;
}
/* Simple tooltip CSS */
div.tooltip {
position: absolute;
background-color: rgba(255,255,255,1);
padding: 10px;
border: 1px solid #ddd;
font-family: Arial;
font-size: 13px;
font-weight: bold;
color: #7c795d;
transition: opacity 500ms linear;
-moz-transition: opacity 500ms linear;
-webkit-transition: opacity 500ms linear;
transition-delay: 500ms
-moz-transition-delay: 500ms;
-webkit-transition-delay: 500ms;
-moz-box-shadow: 4px 4px 12px rgba(0,0,0,.5);
-webkit-box-shadow: 4px 4px 12px rgba(0,0,0,.5);
box-shadow: 4px 4px 12px rgba(0,0,0,.5);
-moz-border-radius: 15px;
border-radius: 15px;
}
.noPointers{
pointer-events:none;
}
.pipelinePoint .circlePoint.active {
fill: orangered;
fill-opacity: 1;
stroke-width: 25px;
stroke-opacity: .5;
}
.pipelinePoint {
stroke-opacity: 1;
fill-opacity: 0.5;
}
.pipelinePoint .circlePoint {
transition: stroke-width 250ms linear;
-moz-transition: stroke-width 250ms linear;
-webkit-transition: stroke-width 250ms linear;
}
/*.pipelinePoint .circlePoint.hover {
fill: blue;
}*/
.circlePoint {
fill-opacity: 0.5;
transition: stroke-width 250ms linear;
-moz-transition: stroke-width 250ms linear;
-webkit-transition: stroke-width 250ms linear;
}
.point-paths path {
/*
fill: #eee;
stroke: #aaa;
*/
stroke-opacity: 0;
fill-opacity: 0;
}

Answer 1

You've filled your circles, but they have do not have a stroke color. So, your css animation is running, there's just nothing to see:
.pipelinePoint .circlePoint.active {
fill: orangered;
stroke: orangered;
fill-opacity: 1;
stroke-width: 25px;
stroke-opacity: .5;
}
Updated fiddle.