A monokai theme for the JSONView chrome extension (https://chrome.google.com/webstore/detail/jsonview/chklaanhfefbnpoihckbnefhakgolnmc) Preview: http://i.imgur.com/v9UqVKr.png

monokai-JSONView.css

body {
  background: #333333;
  color: #ddd;
  white-space: pre;
  font-family: monospace;
}

a {
  color: #ff9000;
}

.property {

}

.type-null {
  color: gray;
}

.type-boolean {
  color: #bc69ff;
}

.type-number {
  color: #bc69ff;
}

.type-string {
  color: #e4e06d;
}

.callback-function {
  color: grey;
}

.collapser {
  left: -16px;
  top: 4px;
  color: #fff;
  border-radius: 10px;
  margin-left: -4px;
  background: rgba(0,0,0,.6);
  padding: 0 !important;
  height:16px;
  width: 16px;
  text-align: center;
}

.collapser:after {
  display: block;
  content: "-";
  line-height: 16px;
  
}

.collapsed > .collapser:after {
  content: "+";
  line-height: 16px;
}

.collapsed .collapser {
  background: #5e9c00;
}

.ellipsis:after {
  content: " … ";
  color: gray;
}

.collapsible {
  margin-left: 2em;
}

.hoverable {
  padding: 4px;
  border-radius: 3px;
  border-left: 1px solid transparent;
}

.collapsible .hovered {
  background-color: #444444;
}

.collapser {
  padding-right: 10px;
  padding-left: 6px;
}

Excellent :)