Mermaid support for Pico CMS (Nextcloudapp Version 1.0.10) in Nextcloud 19.0.3

Hello anyone,

my intention is to make chart diagrams in a markdown file from Pico CMS. In normal md-Files on nextcloud it works, but not when I do it in md-Files in Pico-CMS app in nextcloud. Must I install a plugin or something else that it work in Pico CMS md-Files?
The syntax for the mermaid support in markdown-files of nextcloud is mermaid [then the code for chart, diagram, etc.]
Has anyone a idea?