How to fix color issues with Mermaid?

[Sun-ZhenXing]

There are some color issues with the erDiagram in night mode.

Test code:

```mermaid
erDiagram
    Category ||--o{ Category: "类目是树形结构"
    Category ||--o{ Shop: "每个店铺都在一个一级类目中"

    Category {
        int id PK "ID"
        int pid FK "父类目 ID"
        string name "类目名称"
        int star "星级"
        string remark "备注"
        bool is_deleted "是否删除"
        int version "乐观锁"
        datetime created_at "创建时间"
        datetime updated_at "更新时间"
    }
```

[Mister-Hope]

I think at least the demo is working, and I think I override all color variables. I will check that later

[Mister-Hope]

I am not overriding all variables, and I have made several prs upstream, this shall be fixed later

[Mister-Hope]

mermaid-js/mermaid#4931

[Sun-ZhenXing]

Thank you for your feedback.

[Mister-Hope]

Fixed in 7279e7c