Blurred Lines

[JAA]

I want to draw a polygon, for simplicity let's make it a triangle.

var graphics = new PIXI.Graphics();
graphics.lineStyle(5, 0xFFFFFF, 1);
graphics.moveTo(10, 10);
graphics.lineTo(100, 10);
graphics.lineTo(50, 100);
graphics.lineTo(10, 10);
container.addChild(graphics);

The question is this: How is the best way to add a black shadow to both sides on the lines, so it is pure black just to the left and right of the line, then fades by alpha out to about 5 pixels either side of the line?

Effectively I want a blurred black line of about 15 pixels (with a solid center which fades in alpha at the outer edges) with a solid white line of 5 pixels right in the middle of the black blurred line.