How to set nvd3 tooltip border

Question

I'm trying to make this tool tip position relative to parent div
this is how I implement the webpage:

<div id="parent"> <div id="chart"> <svg style="height:500px"> </svg> </div> </div> 

using css:

 #parent { margin-top:300px; border: solid blue; height: 600px; } #chart { border: solid red; width:500px; float:left; height: 500px; text-align: center; font-weight: bold; margin-bottom: 2em; } svg { width: 100%; } 

I found chartContainer in the chartContainer file, but I could not edit it.
So, are there any possible solutions?