The adjust_luminance() function

Get a palette of 8 pastel colors from the RColorBrewer package.

pal <- RColorBrewer::brewer.pal(8, "Pastel2")

Create lighter and darker variants of the base palette (one step lower, one step higher).

pal_darker  <- pal |> adjust_luminance(-1.0)
pal_lighter <- pal |> adjust_luminance(+1.0)

Create a tibble and make a gt table from it. Color each column in order of increasingly darker palettes (with data_color()).

dplyr::tibble(a = 1:8, b = 1:8, c = 1:8) |>
  gt() |>
  data_color(
    columns = a,
    colors = scales::col_numeric(
      palette = pal_lighter,
      domain = c(1, 8)
    )
  ) |>
  data_color(
    columns = b,
    colors = scales::col_numeric(
      palette = pal,
      domain = c(1, 8)
    )
  ) |>
  data_color(
    columns = c,
    colors = scales::col_numeric(
      palette = pal_darker,
      domain = c(1, 8)
    )
  )

Warning: Since gt v0.9.0, the `colors` argument has been deprecated.
• Please use the `fn` argument instead.
This warning is displayed once every 8 hours.

a	b	c
1	1	1
2	2	2
3	3	3
4	4	4
5	5	5
6	6	6
7	7	7
8	8	8