[Bug Report] 渲染 mermaid 脑图时，节点重叠在一起

[magicfold]

Prerequisites

• [ ] There isn't an existing issue that reports the same bug to avoid duplicates.
• [ ] The provided information offers a minimal reproducible example of the bug.
• [ ] For Q&A, please open a GitHub Discussion instead.

Describe the Bug

期望效果：

mindmap
    Root
        A
            B
            C

实际效果：

Reproduction Steps

No response

System Information

No response

Contributing

None