darken(base00, pct) returns base00, so telescope's panes never get a ground of their own

Inspect base16-colorscheme.lua around line 533 and the Telescope highlight definitions. Run the stock default-dark or default-light reproduction in Neovim, then verify that TelescopeNormal, TelescopeBorder, and TelescopeResultsTitle have a distinct background while the other darken callers retain their behavior.

The telescope branch means to put the picker on a background one shade off the rest:

local darkerbg = darken(M.colors.base00, 0.1)   -- base16-colorscheme.lua:533

but darken blends its argument towards base00 rather than darkening it, so this particular call is an identity — r + (r - r) * pct == r — for every scheme and every pct. TelescopeNormal, TelescopeBorder and TelescopeResultsTitle land on the ordinary background, while TelescopePromptNormal and TelescopeSelection, which come from base02, do move.

Repro, stock scheme, no telescope needed:

require("base16-colorscheme").setup("default-dark")
for _, g in ipairs({ "Normal", "TelescopeNormal", "TelescopePromptNormal" }) do
  print(g, ("#%06X"):format(vim.api.nvim_get_hl(0, { name = g }).bg))
end
-- Normal                #181818
-- TelescopeNormal       #181818   <- expected a shade under Normal
-- TelescopePromptNormal #343434

default-light behaves the same way: Normal and TelescopeNormal are both #F8F8F8.

It shows up as more than a missing shade in a terminal with background opacity, since a cell whose background equals the default background is drawn translucent — the results pane comes out transparent under an opaque prompt.

The other seven callers rely on blending towards base00 (darken(base0B, 0.85) is how DiffAdd's background is arrived at), so the fix belongs at the call site rather than in the function. PR follows.