How to "box" the output of "summary()" in Rmarkdown

[blackish952]

I have seen this post from stackoverflow.com:

How to create R-markdown sections inside a R code chunk? With proper code display

and one of the responders, Cedric, impressed me with the way he or she boxed the output of summary() command in R.

I understand that the user used Sweave to create such a great output.
I am curious that whether there is a way to use Knit to output to a PDF file in the similar fashion.

Thank you!

[cderv]

Here is an answer for HTML output.

You can change the look of the html using a custom css, and it is easy to assign a specific class for the chunk output using class.output chunk options

---
title: Test box output
output:
  html_document: default
---

```{css, echo = FALSE}
.bordered {
  border: solid;
}
```


```{r, class.output = ".bordered"}
summary(lm(data = mtcars, mtcars[, 1] ~ mtcars[, 2]))
```

I let someone else gives an answer for PDFoutput.