style.css

.nodemap .node { /* Nodes of a nodemap */
  z-index:100; /* needed otherwise the canvas will cover the nodes */

  /* Blue background gradient to black - diagonal taken from http://www.colorzilla.com/gradient-editor/ */
  background: rgb(0,104,196); /* Old browsers */
  background: -moz-linear-gradient(-45deg,  rgba(0,104,196,1) 0%, rgba(0,0,0,1) 100%); /* FF3.6+ */
  background: -webkit-gradient(linear, left top, right bottom, color-stop(0%,rgba(0,104,196,1)), 
    color-stop(100%,rgba(0,0,0,1))); /* Chrome,Safari4+ */
  background: -webkit-linear-gradient(-45deg,  rgba(0,104,196,1) 0%,rgba(0,0,0,1) 100%); /* Chrome10+,Safari5.1+ */
  background: -o-linear-gradient(-45deg,  rgba(0,104,196,1) 0%,rgba(0,0,0,1) 100%); /* Opera 11.10+ */
  background: -ms-linear-gradient(-45deg,  rgba(0,104,196,1) 0%,rgba(0,0,0,1) 100%); /* IE10+ */
  background: linear-gradient(135deg,  rgba(0,104,196,1) 0%,rgba(0,0,0,1) 100%); /* W3C */
  
  text-decoration: none;
  border: 1px solid black;

  display: table;
  width: 100px;
	height: 100px;
  -moz-border-radius: 50px;
	-webkit-border-radius: 50px;
	border-radius: 50px;
  padding: 5px;
}

.nodemap .parent { /* Nodes of a nodemap which are also marked as parent (they have a different color by CSS override) */
  background: #61636b; /* Old browsers */
  background: -moz-linear-gradient(top,  #61636b 0%, #828c95 36%, #28343b 100%); /* FF3.6+ */
  background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#61636b), color-stop(36%,#828c95), color-stop(100%,#28343b)); /* Chrome,Safari4+ */
  background: -webkit-linear-gradient(top,  #61636b 0%,#828c95 36%,#28343b 100%); /* Chrome10+,Safari5.1+ */
  background: -o-linear-gradient(top,  #61636b 0%,#828c95 36%,#28343b 100%); /* Opera 11.10+ */
  background: -ms-linear-gradient(top,  #61636b 0%,#828c95 36%,#28343b 100%); /* IE10+ */
  background: linear-gradient(to bottom,  #61636b 0%,#828c95 36%,#28343b 100%); /* W3C */
}

.nodemap .node>p { /* Visualize text paragraphs centered in the nodes */
  color: white;
  display: table-cell;
  vertical-align: middle;
  text-align: center;
}

.nodemap .parent>p {
  color: #CCCCCC;
}

.nodemap div.node>p { /* Makes p elements children of div nodes
                         unselectable with the mouse cursor (CSS3) */
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  cursor: default;
}

.nodemap * { /* Apply a font to all the nodemap elements (div, a, whatever) */
    font-family: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif;
}

.nodemap { /* The nodemap itself */
  /* Elements in this map are positioned as 'absolute', but everything is
     relative to this map area */
  position: relative;
  display: block;
  height: 100%;
  overflow: visible;
}