Add default class to nodes and fix styles

packages/mermaid/src/diagrams/er/erDb.ts

@@ -45,7 +45,7 @@ const addEntity = function (name: string, alias = ''): EntityNode {
       alias,
       shape: 'erBox',
       look: getConfig().look || 'default',
-      cssClasses: [],
+      cssClasses: ['default'],
       cssStyles: [],
     });
     log.info('Added new entity :', name);

packages/mermaid/src/diagrams/er/styles.js

@@ -36,8 +36,8 @@ const getStyles = (options) =>
   .node rect,
   .node circle,
   .node ellipse,
-  .node polygon,
-  .node path {
+  .node polygon
+  {
     fill: ${options.mainBkg};
     stroke: ${options.nodeBorder};
     stroke-width: 1px;