How to export RMarkdown file to HTML document with two columns?

rmarkdown file:

#### Put in your css file or directly in rmarkdown

<style>
  .col2 {
    columns: 2 200px;         /* number of columns and width in pixels*/
    -webkit-columns: 2 200px; /* chrome, safari */
    -moz-columns: 2 200px;    /* firefox */
  }
  .col3 {
    columns: 3 100px;
    -webkit-columns: 3 100px;
    -moz-columns: 3 100px;
  }
</style>

#### This section will have three columns

<div class="col3">
**1** one  
**2** two  
**3** three  
**4** four  
**5** five  
**6** six  
**7** seven  
**8** eight  
**9** nine  
</div>

#### This section will have two columns

<div class="col2">
```{r}
head(mtcars)
tail(mtcars)
```
</div>

Gives me this

---

Edit

To be more precise with the column elements, you can use a div for each set of elements:

Rmd file

<style>
.column-left{
  float: left;
  width: 33%;
  text-align: left;
}
.column-center{
  display: inline-block;
  width: 33%;
  text-align: center;
}
.column-right{
  float: right;
  width: 33%;
  text-align: right;
}
</style>

#### This section will have three columns

<div class="column-left">
**1** one  
**2** two  
</div>
<div class="column-center">
**3** three  
**4** four  
**5** five  
**6** six  
</div>
<div class="column-right">
**7** seven  
**8** eight  
**9** nine  
</div>

Gives me