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Body, HtmlView and list text were 15 while the gjsify theme (GTK 11 pt at 96 dpi) uses 14.67.
The first commit aligned app.css and the vendored adwaita.css.

Second commit: stop re-declaring the ramp

app.css kept its own .title-* and .body font sizes on top of the theme it imports, and the
vendored adwaita.css was a snapshot old enough to predate the theme's current sizes — so the app
rendered a ramp matching neither GTK nor the theme.

Now the vendored copy is resynced from gjsify (which gained the full libadwaita ramp in
gjsify/gjsify#2583) and app.css keeps only what is really app-specific: the 12/12 margins and an
explicit HtmlView size. One source for the ramp, so the next theme change arrives with the
dependency bump instead of needing a second edit here.

Visible side effect of the resync, worth knowing before merge: .adw-preferences-group-title
11 → 14.67 and .adw-preferences-group-description 12 → 14.67. The old values came from the stale
snapshot; gjsify's canonical theme wins. Checked on the device in light, dark and at
font_scale 1.3 — no clipping, the groups just read at the size GTK uses.

Device verification

Galaxy S9, Android 10, density 3.5, built against a locally linked gjsify that carries #2583.
Line pitch measured by row projection of the screenshots:

	before	after
editor gutter pitch	73 px	61 px
tutorial code block pitch	73 px	61 px
prose pitch	62 px	62 px (unchanged)
code : prose	1.18	0.98 (GTK reference 1.00)

Matrix walked: light and dark, default palette plus a custom primary and a custom accent,
font_scale 1.0 and 1.3, portrait and landscape plus a live rotation, Learn/Code/Debug/Play,
keyboard open in the editor, Preferences, About and Details.

Checks: check:format, check:lint, check:versions all green.

Needs a gjsify release containing gjsify/gjsify#2583 — this PR was verified against a
gjsify link build, not a published version, so the dependency bump has to land before or with it.

Second and third commit: the app's half of the interface scale

The prose pitch row above (62 px before, 62 px after) was the honest answer at the time and also
the clue: the tutorial's body text was not following the theme at all. The MDX compiler puts
paragraph on every prose block, it is not an Adwaita class, so the gjsify theme does not carry
it — on GTK an undeclared label inherits the document font and looks right, on NativeScript it
falls through to the Android default text size, which no stylesheet reaches. Same shape as the
editor find in #2583, and the same fix: packages/app-android/app/app.css now states 14.67 for
.paragraph and for .gtksource-view (the class GtkSourceView puts on itself, whose driver
needs a declared size or keeps its own DEFAULT_FONT_SIZE).

With that, every text surface is reachable from the stylesheet, which is what the interface scale
needs. gjsify's new @gjsify/adwaita-nativescript/app-scale (third commit of gjsify/gjsify#2583)
multiplies every length in the sheet — font sizes and paddings, min-heights, radii, icon boxes —
by one factor. This PR is the app's half:

• InterfaceScaleService owns the stored value: gschema key interface-scale as a string, either
  auto or a factor such as 1.25. A stored factor that is not offered maps to its nearest entry.
• It hands the processed stylesheet to registerAppScaleCss via import appCss from "./app.css?inline" — ?inline, not ?raw, so Tailwind is expanded and the @imports inlined —
  and applies before themeService.init, which reappends the sheet whenever it rewrites the theme.
• The Preferences row is a combo: "Automatic (114%)" first, then 100% to 150% in tenths. Picking
  Automatic again is the reset, so the group needs no second button. The row only exists where a
  scale service is passed in, so the GNOME and web dialogs are unchanged.
• Text and spacing follow immediately; icon sizes are baked at render time and follow after a
  restart, which the group description states.

Device verification

Galaxy S9, density 3.5, 411.4 dp wide → derived factor 1.143. Measured at fresh starts:

	100%	auto (114%)	150%
editor gutter pitch	61 px	68 px	90 px
selected tab pill	136 px	156 px	205 px
header bar height	163 px	186 px	245 px
tutorial prose pitch	66 px	74 px	—

The prose row before the .paragraph fix: 62 px at 100% and 63 px at auto, while the title-2
next to it grew 54 → 61. After it, the text band is 49 → 57 px tall and the pitch 66 → 74.

No double scaling with the system font size: at font_scale 1.3 and auto the editor pitch is
85 px against 68 px.

Matrix walked again on the final build: light and dark, default palette plus a custom accent,
font_scale 1.0 and 1.3, portrait and landscape plus a live rotation, all four pages, keyboard
open in the editor, Preferences, About and its Details page. No clipping.

Known limitation, not fixed here: the generated .blp sets margin-top/bottom: 12 directly on
each prose label, and in NativeScript a value set on the view wins over CSS, so those block margins
stay at 12 dip while the text grows. The native overflow menu and the combo's AlertDialog are
Android popups and follow the system font scale, not the app scale.

Checks

gjsify run check (all tsc projects), check:format, check:lint, check:versions and the i18n
gates green; catalogues regenerated with the new msgids and the German one filled.
check:metainfo fails locally on a weblate 403 (url-not-reachable), environmental.

Ordering, unchanged but now larger: app-android imports
@gjsify/adwaita-nativescript/app-scale, a subpath 0.64.27 does not publish. CI here fails until a
gjsify release carries #2577, #2579 and #2583 together, and the dependency bump lands with it.