How can I center the output of general R results in Quarto?

In a Quarto document that creates HTML output, I can print general R object and the results will be left aligned in Quarto. How can I center or right align general R objects? In addition, is there a way I could add a gray background to this output?

The code provided is from a default template Quarto file, and the image shows the results being left aligned by default.

```{r}
mtcars
```

Extending from this answer,

---
title: "Test"
format: html
css: style.css
---

```{r}
#| classes: styled-output
mtcars
```

style.css

.styled-output .cell-output {
  background-color: #c8cac8;
}

.styled-output .cell-output pre {
  max-width: fit-content;
  margin-left: auto;
  margin-right: auto;
}