Catch the README and FEATURES up with the themes and 0.16.21

Themes were not in "What's in it" at all, which is odd for something a
reader sees before anything else. There is now a bullet for the twelve,
saying that palette and light-or-dark are separate choices and that a
palette which would not meet the contrast this app claims is not written.

FEATURES lists the six new palettes and what each borrows for its light
half, and records the rule that changed with them: body text used to be
checked and then accepted or rejected, which would have turned away five
of the six over a bar their designers never aimed at, so it is now lifted
along its own hue like every other text tone. Twenty-one of the twenty-two
borrowed halves need at least one lift.

The message-theming entry gained the second switch, including why the
first one alone did nothing for most real mail.

The Stalwart section records what the release is validated against rather
than only what it requires: 0.16.21, run against a real instance, with the
four client-visible JMAP changes named. The mock section gains its third
switch and says it tracks the current release, confirms each behaviour
against a real server first, and rewrites rather than deletes the test
that pinned an old behaviour.

FEATURES.md

@@ -365,7 +365,15 @@ same query string — so what it builds can be read, edited and learned from.
   these headers shows nothing.
 - **Message body theming** is off by default — sender HTML is left exactly as it
   was designed, on a light card. One setting lets mail that brings no colours of
-  its own follow the app's theme instead.
+  its own follow the app's theme instead. That is a low bar in practice: one
+  `color:#FFFFFF` on one button label opts a whole message out, so for mail
+  built from a template it changed nothing. A second setting, off unless the
+  first is on, forces the theme over the sender's own colours. It tells a
+  *sheet* the design sits on, like a white wrapper table, from a *painted
+  surface* like a button or a banner, by relative luminance: the first is
+  neutralised so the bright card goes away, the second is kept whole so its
+  label stays readable on it. Nothing the sender wrote is removed, so the
+  switch is reversible, and print is unaffected either way.
 
 ### Conversations
 
@@ -1019,11 +1027,17 @@ at two.
 | **Gruvbox** | |
 | **Rosé Pine** | Dawn as its light half |
 | **Tokyo Night** | Day as its light half |
+| **Catppuccin** | Mocha and Latte |
+| **Solarized** | Light and dark are both original to it, and share one set of accents |
+| **Ayu** | |
+| **Kanagawa** | Wave, with Lotus as its light half |
+| **Everforest** | The medium-contrast variant of each side |
+| **Primer** | The colours behind GitHub's design system. Named for the system, not for GitHub, which has not endorsed anything here |
 
 Every one has both halves, so the top-bar toggle only ever changes the side and
 never the colours. Accent colours still sit on top of any of them.
 
-The four borrowed palettes are the work of their own projects and are used
+The ten borrowed palettes are the work of their own projects and are used
 under the MIT licence — see [NOTICE](NOTICE). Only the published colour values
 are used, taken from each project's own repository; the values as fetched are
 recorded in `.palette-sources/palettes-upstream.md`.
@@ -1037,11 +1051,20 @@ anything that falls short, towards white on a dark ground and towards black on
 a light one so the hue survives. The script refuses to write a palette that
 would not pass.
 
-That check is not a formality. **Every one of the nine palette halves needed at
-least one lift**, because these palettes are designed for code editors rather
-than for prose at this size: Dracula's comment grey is 3.03:1 on its own
-background, and Rosé Pine's gold is 2.7:1 on Dawn. Shipping them as published
-would have quietly ended the WCAG AA claim two sections down.
+That check is not a formality. **Twenty-one of the twenty-two palette halves
+needed at least one lift**, because these palettes are designed for code
+editors rather than for prose at this size: Dracula's comment grey is 3.03:1 on
+its own background, and Rosé Pine's gold is 2.7:1 on Dawn. Shipping them as
+published would have quietly ended the WCAG AA claim two sections down.
+
+Body text is lifted the same way, which it was not at first. It used to be
+checked and then either accepted or rejected, and that rule would have turned
+away five of the six palettes added in September 2026: most of them target
+around 4.5:1 for body text, their own goal, where ihasmail asks 7:1 of the text
+a reader looks at all day. Rejecting a palette over a bar its designers never
+aimed at is the wrong answer when the same arithmetic already adjusts muted
+text, links and accents. Solarized Light moves 4.13 to 7.07 that way; Primer
+needed nothing in either half.
 
 ---