### Bug description

* Mac OS 12.6.3.
* Latest Quarto downloaded a few minutes ago by pulling and building locally.
* Behavior checked on Safari, Chrome and Firefox, and behavior is the same.
* Running Quarto from the command line
* Complete repo is [here](https://github.com/bryanhanson/CSR) and the page with the bad behavior is [here](https://github.com/bryanhanson/CSR/tree/master/posts/2022-09-26-Linear-Alg-Notes-Pt4).

Not sure what's going on here.  I'm hoping you all will recognize the problem.  Glad to build a MWE if the problem is not immediately apparent.  This was working, not sure when it broke.

A Mermaid diagram on my blog [here](https://chemospec.org/posts/2022-09-26-Linear-Alg-Notes-Pt4/Linear-Alg-Notes-Pt4.html) has the wrong colors, the html formatting of some labels is displayed rather than rendered, and the arrows appear to be pure white (they seem invisible/missing but under the right conditions you can see them as white on a barely grey background).

The Mermaid code works fine if I put it in [Mermaid Live](https://mermaid.live/edit#pako:eNqNkstOwzAQRX_FMhtXKipdsImqIEpJn3QDS2-cZNpa8qM4NiVE-XfcKUGiyoKdde6ZK4_lhha2BJrQnbKn4iCcJ28zbh6ZUIpo4Z0soCKT3I1SYsgn0QNye5uSJ-bs6Tofx9wM4jAqM1ZYFbTpaxn_WFGbsuo9CAd92rlsimXPLByP4EhUhNkHJRxa3cyvl7G4xj-8edNM8hSkP4CbjPIULVmRSl6mHtq2Uxeo2j-aNB_gvMwVoLhAcdk0MSql2FsjlPwSXbzEeIWxsU4LhXiFeM2qWms43y_ebo1sw7qWiDaIXpgswXjp60E3ucVC6_zBooul24vNTeVrBWROdlKp5CbLsrvsvqOLXrrspateur2idEg1xM1kGb9Sww0hnMa31cBpEo8l7ERQnlNu2qiK4O1rbQqaeBdgSMOxFB5mcWcn9AW2379o2lU), here's a png of what it should look like:

![mermaid-diagram-2023-02-17-210328](https://user-images.githubusercontent.com/140350/219877509-881f0aea-09bb-4dba-8553-8a58f34ba29d.png)

Screenshot of (part of) the mis-behaving version (also visible at the link to the post above):


<img width="781" alt="Screen Shot 2023-02-18 at 10 21 00 AM" src="https://user-images.githubusercontent.com/140350/219877794-9c73fefd-80c8-4bce-b303-a5100b922cf0.png">

Any ideas of what's happening?  Thank you!

### Checklist

- [X] Please include a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
- [X] Please [format your issue](https://quarto.org/bug-reports.html#formatting-make-githubs-markdown-work-for-us) so it is easier for us to read the bug report.
- [X] Please document the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
- [X] Please document the operating system you're running. If on Linux, please provide the specific distribution.
cscheid
2023-02-18T16:50:51Z
bryanhanson
bug mermaid
v1.4
open
Mermaid diagram color scheme and formating not as specified
https://github.com/quarto-dev/quarto-cli/issues/4421