One other follow up, if I may: does it matter that I am creating not just
html_document format but
flexdashboard pages? I have a sample call below (with output_options commented out), are you saying I could specify the theme to null and just update the css to have all the proper formatting? And the css would be specifying links to external dependencies? Thank you again so much for your help.
(by the way, for defining output_options as self_contained = FALSE to work, I couldn't call flexdashboard from the render function, and instead had to define it in the YAML in the Rmd file. Not sure if that's a feature or a bug).
orientation = "rows",
#output_options = list(self_contained = FALSE, lib_dir = "lib"),
output_file = html_district_1,
params = list(file_path = data, set_title = paste0(district_name, " District, ", version),
student_data = student_data_var, includeT2 = includeT2, version = version))