refactor: update RTE to use base styles, cleanup Lumo CSS (#10056)

Author: web-padawan

packages/rich-text-editor/src/styles/vaadin-rich-text-editor-base-styles.js

@@ -368,12 +368,6 @@ export const content = css`
     padding: 0.125rem 0.25rem;
   }
 
-  pre {
-    white-space: pre-wrap;
-    margin-block: var(--vaadin-padding-s);
-    padding: var(--vaadin-padding-container);
-  }
-
   img {
     max-width: 100%;
   }
@@ -417,7 +411,7 @@ const toolbar = css`
   }
 
   [part~='toolbar-button']::before {
-    background: currentcolor;
+    background: currentColor;
     content: '';
     display: block;
     height: var(--vaadin-icon-size, 1lh);

packages/rich-text-editor/src/vaadin-rich-text-editor.js

@@ -117,6 +117,12 @@ class RichTextEditor extends RichTextEditorMixin(
     return richTextEditorStyles;
   }
 
+  static get lumoInjector() {
+    return {
+      includeBaseStyles: true,
+    };
+  }
+
   /** @protected */
   render() {
     return html`