screen-demo/map-example/cesium/Source/Widgets/ProjectionPicker/ProjectionPicker.css

span.cesium-projectionPicker-wrapper {
  display: inline-block;
  position: relative;
  margin: 0 3px;
}

.cesium-projectionPicker-visible {
  visibility: visible;
  opacity: 1;
  transition: opacity 0.25s linear;
}

.cesium-projectionPicker-hidden {
  visibility: hidden;
  opacity: 0;
  transition: visibility 0s 0.25s, opacity 0.25s linear;
}

.cesium-projectionPicker-wrapper .cesium-projectionPicker-none {
  display: none;
}

.cesium-projectionPicker-wrapper .cesium-projectionPicker-dropDown-icon {
  box-sizing: border-box;
  padding: 0;
  margin: 3px 0;
}

.cesium-projectionPicker-wrapper .cesium-projectionPicker-buttonPerspective,
.cesium-projectionPicker-wrapper .cesium-projectionPicker-buttonOrthographic {
  margin: 0 0 3px 0;
}

.cesium-projectionPicker-wrapper
  .cesium-projectionPicker-buttonPerspective
  .cesium-projectionPicker-iconOrthographic {
  left: 100%;
}

.cesium-projectionPicker-wrapper
  .cesium-projectionPicker-buttonOrthographic
  .cesium-projectionPicker-iconPerspective {
  left: -100%;
}

.cesium-projectionPicker-wrapper .cesium-projectionPicker-selected {
  border-color: #2e2;
  box-shadow: 0 0 8px #fff, 0 0 8px #fff;
}