style: add min-height of 400px to map container

Author: ochafik

examples/map-server/mcp-app.html

@@ -27,6 +27,7 @@
         html, body, #cesiumContainer {
             width: 100%;
             height: 100%;
+            min-height: 400px;
             margin: 0;
             padding: 0;
             overflow: hidden;