Add new colors argument to README

README.Rmd

     - [Duotone](#duotone)
     - [Solarized](#solarized)
 - [Theme Settings](#theme-settings)
-- [Adding Custom CSS](#adding-custom-css)
+- [Colors](#colors)
 - [Fonts](#fonts)
+- [Adding Custom CSS](#adding-custom-css)
 
 ## Installation
 
 
 ## Theme Settings
 
-The theme functions listed above are just wrappers around the central function of this package, `style_xaringan()`.
+The theme functions listed above are wrappers around the central function of this package, `style_xaringan()`.
 If you want to start from the default **xaringan** theme and make a few modifications, start there.
 
 All of the [theme template variables][template-variables] are repeated in each of the theme functions (instead of relying on `...`) so that you can use autocompletion to find and change the defaults for any theme function.
 To override the default value of any theme functions, set the appropriate argument in the theme function.
 A table of all template variables is included in [`vignette("template-variables", "xaringanthemer")`][template-variables].
 
-As an example, try loading `xaringanthemer`, type out `duo_theme(` and then press <kbd>Tab</kbd> to see all of the theme options.
+As an example, try typing out `style_duo_accent(` and then press <kbd>Tab</kbd> to see all of the theme options.
 
-All of the theme options are named so that you first think of the element you want to change, then the property of that element.
+The arguments of each theme function are named so that you can first think of the element you want to change, then the property of that element.
 
 Here are some of the `text_` theme options:
 
 cat(paste0("- `", tvv[grepl("^title_slide_", tvv)], "`"), sep = "\n")
 ```
 
+## Fonts
+
+[adding-custom-css]: #adding-custom-css
+
+```{r child="man/fragments/_fonts.Rmd"}
+```
+
+## Colors
+
+```{r child="man/fragments/_colors.Rmd"}
+```
+
 ## Adding Custom CSS
 
 You can also add custom CSS classes using the `extra_css` argument in the theme functions.
 
 ```r
 extra_css <- list(
-  ".red"   = list(color = "red"),
   ".small" = list("font-size" = "90%"),
   ".full-width" = list(
     display = "flex",
 
 ```{r results='asis', echo=FALSE}
 extra_css <- list(
-  ".red"   = list(color = "red"),
   ".small" = list("font-size" = "90%"),
   ".full-width" = list(
     display = "flex",
 ```
 
 This is most helpful when wanting to define helper classes to work with the [remark.js][remarkjs] `.class[]` syntax.
-Using the above example, we could color text red `.red[like this]` or write `.small[in smaller font size]`.
-
-## Fonts
+Using the above example, we could add slide text `.small[in smaller font size]`.
 
-[adding-custom-css]: #adding-custom-css
-
-```{r child="man/fragments/_fonts.Rmd"}
-```
 
 ```{r child="man/fragments/_thanks.Rmd"}
 ```

README.md

       - [Duotone](#duotone)
       - [Solarized](#solarized)
   - [Theme Settings](#theme-settings)
-  - [Adding Custom CSS](#adding-custom-css)
+  - [Colors](#colors)
   - [Fonts](#fonts)
+  - [Adding Custom CSS](#adding-custom-css)
 
 ## Installation
 
 
 ## Theme Settings
 
-The theme functions listed above are just wrappers around the central
+The theme functions listed above are wrappers around the central
 function of this package, `style_xaringan()`. If you want to start from
 the default **xaringan** theme and make a few modifications, start
 there.
 [`vignette("template-variables",
 "xaringanthemer")`](vignettes/template-variables.md).
 
-As an example, try loading `xaringanthemer`, type out `duo_theme(` and
-then press <kbd>Tab</kbd> to see all of the theme options.
+As an example, try typing out `style_duo_accent(` and then press
+<kbd>Tab</kbd> to see all of the theme options.
 
-All of the theme options are named so that you first think of the
-element you want to change, then the property of that element.
+The arguments of each theme function are named so that you can first
+think of the element you want to change, then the property of that
+element.
 
 Here are some of the `text_` theme options:
 
   - `title_slide_background_size`
   - `title_slide_background_position`
 
-## Adding Custom CSS
-
-You can also add custom CSS classes using the `extra_css` argument in
-the theme functions. This argument takes a named list of CSS definitions
-each containing a named list of CSS property-value pairs.
-
-``` r
-extra_css <- list(
-  ".red"   = list(color = "red"),
-  ".small" = list("font-size" = "90%"),
-  ".full-width" = list(
-    display = "flex",
-    width   = "100%",
-    flex    = "1 1 auto"
-  )
-)
-```
-
-If you would rather keep your additional css definitions in a separate
-file, you can call `style_extra_css()` separately. Just be sure to
-include your new CSS file in the list of applied files in your YAML
-header.
-
-``` r
-style_extra_css(css = extra_css, outfile = "custom.css")
-```
-
-``` css
-/* Extra CSS */
-.red {
-  color: red;
-}
-.small {
-  font-size: 90%;
-}
-.full-width {
-  display: flex;
-  width: 100%;
-  flex: 1 1 auto;
-}
-```
-
-This is most helpful when wanting to define helper classes to work with
-the [remark.js](https://github.com/gnab/remark) `.class[]` syntax. Using
-the above example, we could color text red `.red[like this]` or write
-`.small[in smaller font size]`.
-
 ## Fonts
 
 <!-- Need to set [adding-custom-css] -->
 )
 ```
 
+## Colors
+
+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.
+
+## Adding Custom CSS
+
+You can also add custom CSS classes using the `extra_css` argument in
+the theme functions. This argument takes a named list of CSS definitions
+each containing a named list of CSS property-value pairs.
+
+``` r
+extra_css <- list(
+  ".small" = list("font-size" = "90%"),
+  ".full-width" = list(
+    display = "flex",
+    width   = "100%",
+    flex    = "1 1 auto"
+  )
+)
+```
+
+If you would rather keep your additional css definitions in a separate
+file, you can call `style_extra_css()` separately. Just be sure to
+include your new CSS file in the list of applied files in your YAML
+header.
+
+``` r
+style_extra_css(css = extra_css, outfile = "custom.css")
+```
+
+``` css
+/* Extra CSS */
+.small {
+  font-size: 90%;
+}
+.full-width {
+  display: flex;
+  width: 100%;
+  flex: 1 1 auto;
+}
+```
+
+This is most helpful when wanting to define helper classes to work with
+the [remark.js](https://github.com/gnab/remark) `.class[]` syntax. Using
+the above example, we could add slide text `.small[in smaller font
+size]`.
+
 -----
 
 **xaringanthemer** was built by [Garrick

man/fragments/_colors.Rmd

+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.

vignettes/xaringanthemer.Rmd

 cat(paste0("- `", tvv[grepl("^title_slide_", tvv)], "`"), sep = "\n")
 ```
 
+## Fonts
+
+[adding-custom-css]: #adding-custom-css
+
+```{r child="../man/fragments/_fonts.Rmd"}
+```
+
+## Colors
+
+```{r child="../man/fragments/_colors.Rmd"}
+```
+
 ## Adding Custom CSS
 
 You can also add custom CSS classes using the `extra_css` argument in the theme functions.
 
 ```r
 extra_css <- list(
-  ".red"   = list(color = "red"),
   ".small" = list("font-size" = "90%"),
   ".full-width" = list(
     display = "flex",
 
 ```{r results='asis', echo=FALSE}
 extra_css <- list(
-  ".red"   = list(color = "red"),
   ".small" = list("font-size" = "90%"),
   ".full-width" = list(
     display = "flex",
 ```
 
 This is most helpful when wanting to define helper classes to work with the [remark.js][remarkjs] `.class[]` syntax.
-Using the above example, we could color text red `.red[like this]` or write `.small[in smaller font size]`.
-
-## Fonts
-
-[adding-custom-css]: #adding-custom-css
-
-```{r child="../man/fragments/_fonts.Rmd"}
-```
+Using the above example, we could add slide text `.small[in smaller font size]`.
 
 ```{r child="../man/fragments/_thanks.Rmd"}
 ```