When designing your xaringan theme,
you may have additional colors in your desired color palette
beyond those used in the accent colors of the mono and duotone styles.

The `style*()` functions in xaringanthemer
include a `colors` argument that lets you 
quickly define a additional colors to use in your slides.
This argument takes a vector of named colors

```r
colors = c(
  red = "#f34213",
  purple = "#3e2f5b",
  orange = "#ff8811",
  green = "#136f63",
  white = "#FFFFFF",
)
```

and creates CSS classes from the color name 
that set the text color — e.g. `.red` —
or that set the background color — e.g. `.bg-red`.
If you use custom CSS in your slides,
the color name is also stored in a CSS variable —
e.g. `var(--red)`.

So slide text like this

```markdown
This **.red[simple]** .white.bg-purple[demo] 
_.orange[shows]_ the colors .green[in action].
```

will be rendered in HTML as

<blockquote>
This <strong><span style="color: #f34213">simple</span></strong>
<span style="color:#FFFFFF;background-color:#3e2f5b;">demo</span>
<em style="color:#ff8811">shows</em>
the colors
<span style="color:#136f63">in action</span>.
</blockquote>

Note that the color names in `colors`
need to be valid CSS names,
so `"purple-light"` will work,
but `"purple light"` will not.
