Give your xaringan slides some style with xaringanthemer within your
slides.Rmd file without (much) CSS.
xaringanthemer currently lives on GitHub.
First, add the
xaringan-themer.css file to the YAML header of your xaringan slides.
Then, in a hidden chunk just after the knitr setup chunk, load xaringanthemer and try one of the theme functions.