diff --git a/backend/fluksio/tui/chart.py b/backend/fluksio/tui/chart.py
index 12d79c9..e50bee3 100644
--- a/backend/fluksio/tui/chart.py
+++ b/backend/fluksio/tui/chart.py
@@ -6,10 +6,11 @@ chart. Nothing is imported for this: a plotting library would be two
 dependencies on a package whose every dependency is argued for in
 `pyproject.toml`, for something a screenful of arithmetic does.
 
-The colours are deliberately not the web's. `--chart-1…5` step one brand hue
-by lightness, which is right against a designed surface and unreadable in a
-terminal — five steps of one hue collapse to one colour on a 16-colour tty.
-Here identity is carried by hue, and the legend names every series anyway.
+The colours are deliberately not the web's. The web draws from the categorical
+`--chart-1…8` palette (DESIGN-GUIDELINES.md, "Chart palette"), fixed values
+chosen against its own surfaces. A terminal has a theme of its own, so these
+are named ANSI colours that the user's terminal maps to its scheme, light or
+dark. Identity is carried by hue, and the legend names every series anyway.
 """
 
 from __future__ import annotations