Drop style improved.

src/Squidex/app/shared/components/markdown-editor.component.scss

@@ -38,4 +38,8 @@ $background: #fff;
             text-decoration: none;
         }
     }
+
+    .drop-text {
+        background: $color-dark-foreground;
+    }
 }

src/Squidex/app/shared/components/rich-editor.component.scss

@@ -38,4 +38,8 @@
             text-decoration: none;
         }
     }
+
+    .drop-text {
+        background: $color-dark-foreground;
+    }
 }