fix: address review round 5 for #7

DESCRIPTION

@@ -29,6 +29,7 @@ Imports:
     sysfonts
 Encoding: UTF-8
 Suggests:
+    quarto,
     testthat (>= 3.0.0),
     tidycensus
 Config/testthat/edition: 3

R/theme.R

@@ -43,6 +43,13 @@
 #'   colored surfaces, slides, or report pages). Set to `TRUE` to
 #'   enable the branded cream canvas.
 #'
+#' @section Device background note:
+#' When saving plots to PNG with `ggsave()`, the transparent default
+#' means the plot area will not have a solid background fill. If you
+#' need a solid background in your exported PNG, set `paper_bg = TRUE`
+#' or add `+ theme(plot.background = element_rect(fill = "white"))`
+#' before saving.
+#'
 #' @section Font size hierarchy:
 #' All text sizes are derived from `font_size` using relative scale factors.
 #' At the default `font_size = 14`: