Both html and pdf format are`eq-prefix: " "` in `_quarto.yml`, HTML output is expected.

```yml
format:
  html:
    theme: cosmo
    crossref:
      chapters: true
      eq-prefix: " "
  pdf:
    documentclass: book
    crossref:
      chapters: true
      eq-prefix: " "
```

 `(@eq-black-scholes)` in PDF format output is not consistent with HTML, PDF has extra space.

### HTML output

<img width="92" alt="html" src="https://user-images.githubusercontent.com/12031874/161662943-fb114bca-fcfb-4bcf-8ef8-2b0226c464bc.png">

### PDF output

<img width="161" alt="pdf" src="https://user-images.githubusercontent.com/12031874/161664945-e92c2e07-11b3-4ad8-a603-79e281b6d30e.png">

when I remove space in `eq-prefix`, some strange happen.

```yml
format:
  html:
    theme: cosmo
    crossref:
      chapters: true
      eq-prefix: " "
  pdf:
    documentclass: book
    crossref:
      chapters: true
      eq-prefix: ""
```

<img width="119" alt="pdf2" src="https://user-images.githubusercontent.com/12031874/161665325-6d34087a-6efd-4f90-8af2-32c7bbc9e844.png">


## Session info

I use latest [geospatial](https://github.com/rocker-org/rocker-versioned2), so Quarto: 0.9.178 and Pandoc: 2.17.1.1


2022-04-05T01:50:36Z
XiangyunHuang
closed
eq-prefix behaves different between PDF and HTML document
https://github.com/quarto-dev/quarto-cli/issues/526