webpack-bundle-analyzer/client/viewer.css

html, body, .treemap {
  width: 100%;
  height: 100%;
  padding: 0;
  margin: 0;
  overflow: hidden;
}

.tooltip {
  font: normal 10px Verdana;
  visibility: hidden;
  position: absolute;
  padding: 5px 10px;
  border-radius: 4px;
  background: #fff;
  border: 1px solid #aaa;
  opacity: 0.7;
  white-space: nowrap;
}