@cesium/engine/Source/Widget/lighter.css

CesiumJS is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin.

.cesium-lighter .cesium-widget-errorPanel {
  background: rgba(255, 255, 255, 0.7);
}

.cesium-lighter .cesium-widget-errorPanel-content {
  border: 1px solid #526f82;
  border-radius: 7px;
  background-color: white;
  color: black;
}

.cesium-lighter .cesium-widget-errorPanel-header {
  color: #b87d00;
}