div#main { position: relative; height: 100%;}
div.node { position: absolute; border: 1px solid red;}
rect.node { stroke: blue; stroke-width: 2; fill: #DDD; cursor: move; box-shadow: 10px 10px 5px #000; }
text.node { dominant-baseline: middle; text-anchor: middle; cursor: move; }
path.edge { fill: transparent; stroke-width: 2; stroke: #888;}
g.drag rect.node { stroke: red; fill: #FDD; }
path.drag { stroke: red; }