Visual theme tokens used by the renderer.

The renderer reads :header, :focus, :selection, :border and :primary; :accent, :muted and :error are general-purpose tokens for apps. Three built-in themes ship, and colors are downgraded to what the terminal supports, so the same theme renders reasonably on truecolor, 256-color, 16-color, and monochrome terminals.

Tokens (each a Harlock.Render.Style.t()):

• :header — table column headers. Default: bold: true.
• :focus — active focus indicator. Default: reverse: true.
• :selection — selected rows / cells. Default: bg: :cyan.
• :border — default box border style. Default: %Style{} (no fg/bg).
• :primary — primary brand / accent surface. Default: fg: :cyan.
• :accent — secondary accent. Default: fg: :magenta.
• :muted — de-emphasised text. Default: dim: true.
• :error — error / destructive surface. Default: fg: :red.

Setting a theme

Harlock.run(MyApp, init_arg, theme: %Harlock.Theme{
  focus:     %Style{reverse: true, fg: :yellow},
  selection: %Style{bg: :blue, fg: :white}
})

# Or use a built-in:
Harlock.run(MyApp, init_arg, theme: Harlock.Theme.builtin(:dark))

Omitting the option uses Harlock.Theme.default/0, which matches the pre-theming hard-coded values byte-for-byte. The default theme is intentionally minimal — apps that want a visible identity pick a built-in or build their own.

Built-in themes

• :default — minimal, terminal-native colors.
• :dark — opinionated dark palette suitable for cave-dwellers.
• :high_contrast — bright primaries / strong borders, biased for readability over aesthetics.

Look up with Harlock.Theme.builtin/1.

Reading inside a callback

def view(model) do
  accent = Harlock.Theme.get(:primary)
  text("hello", style: accent)
end

The runtime stashes the theme in the process dictionary before invoking update/2 and view/1, mirroring the Harlock.Focus pattern. Don't call get/1 outside a Harlock callback — there's nothing in the dictionary.