[Bug] Mermaid code block sets zoom to 0.5

[haegglund]

Description

A Mermaid code block with content sets .markdown-body attribute zoom: 0.5;, which makes the preview way too small. Opening the inspector and changing zoom to 1.0 works, but as soon as the document is edited it reverts to 0.5.

An empty code block does not cause the incorrect behaviour, but one with just diagram type does (e.g. sequenceDiagram).

This happens with or without any custom CSS (in styles/preview.css) present.

Sample Markdown

Title

sequenceDiagram
A->>B: Hello, World!

Loading

MarkEdit Version

1.33.0

MarkEdit Preview Version

1.8.0 (full)

macOS Version

26.5.1

[cyanzhong]

The only possibility is that you manually changed the zoom level from 1.0 to 0.5, by using cmd+/-.

Try this: use preview only mode, or keep side-by-side open and click the preview pane to make sure it has focus.

Then, press cmd-zero to reset the zoom level.