UI-08: migrate theme to Modern Professional Dark

Replaces V3-16's safety-orange identity with the palette actually backing
every fetched Stitch mockup (confirmed by hex-matching against all three
design systems in the Stitch project, not by trusting its declared default).
Ground drops to #0a0a0c with a three-level surface/card stack, primary
becomes Professional Blue (#4090fe), and reference readings move to a new
tertiary orange since blue is no longer free for that role. Re-verified
theme_test.dart's AA contrast assertions against the new values (all pass
with wide margin) and left mounted mode's separate daylight palette alone,
per the ticket's own reasoning.

Also resolves the ticket's named risk: RideMap's speed-gradient hardcoded
hex literal, which would have washed to a single hue now that primary is
blue, now lerps from the theme's own secondary token instead.

Inter is not wired in -- no bundled font asset exists to back the family
name, and setting one without an asset would silently fall back to Roboto.
Documented as a deliberate follow-up rather than a silent gap.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012Xki7YAcc2TiN2PRZJ2tXr

lib/src/ui/theme.dart

@@ -8,40 +8,68 @@ library;
 
 import 'package:flutter/material.dart';
 
-// Matches the launcher icon: near-black tarmac with a safety-orange accent. V3-16
-// warmed the ground fractionally (asphalt, not a generic dark-mode blue-black) and added
-// an instrument-blue tertiary reserved for reference readings -- see the ticket's
-// Direction section for why.
-const _accent = Color(0xFFFF5722);
-const _ground = Color(0xFF120F0D);
-const _surface = Color(0xFF1C1917);
-const _ink = Color(0xFFF2F5F8);
-const _outline = Color(0xFF6E7681);
-const _danger = Color(0xFFE53935);
+// UI-08: "Modern Professional Dark", the design system actually backing every fetched
+// Stitch mockup (confirmed by hex-matching, not by trusting the project's declared
+// default theme — see docs/design/stitch-export/README.md). This supersedes V3-16's
+// safety-orange identity outright, not an extension of it. Full spec:
+// docs/design/stitch-export/design-system-modern-professional-dark.md.
+//
+// `surface-main` (#0a0a0c), not the spec's plain `background`/`surface` (#131313), is
+// used as the app ground: the spec's own prose calls out #0a0a0c as *the* background,
+// with #131313 one step up for a mid-level surface and #16161a another step up for cards
+// — a three-step stack, not two.
+const _ground = Color(0xFF0A0A0C);
+const _surfaceMid = Color(0xFF131313);
+const _ink = Color(0xFFE5E2E1);
+const _outline = Color(0xFF8B919F);
+const _danger = Color(0xFFFFB4AB);
 
-/// Reference readings only (a max, an average) -- never the live figure, which stays
-/// [_accent]. The same colour [RideMap] already uses for its slowest speed bucket,
-/// reused rather than invented, so "instrument blue" means one thing everywhere.
-const _instrumentBlue = Color(0xFF4FC3F7);
+/// Professional Blue. The soul of the interface per the design system's own doc —
+/// primary buttons, the active nav indicator, the user's own location dot, and (via
+/// `RideMap`'s speed gradient) the accent end of the live-path colouring. Replaces
+/// safety-orange as *the* accent everywhere; the app's existing convention of leaving
+/// headline figures (`BigStat`) in plain ink and reserving colour for `StatRow`'s
+/// `reference` values is unchanged by this ticket.
+const _primary = Color(0xFF4090FE);
+
+/// UI-08 decision (the design system doesn't prescribe this split itself): reference
+/// readings (a max, an average) get the warm tertiary orange, never the live figure,
+/// which stays [_primary]. Inverted from V3-16 (blue was the reference colour there)
+/// because blue is now the primary/live colour — a same-hue reference tone would have
+/// been visually indistinguishable from the live one it exists to be told apart from.
+const _referenceOrange = Color(0xFFFFB68C);
 
 const ripprColors = ColorScheme.dark(
-  primary: _accent,
-  onPrimary: Color(0xFF100A06),
-  secondary: _outline,
-  tertiary: _instrumentBlue,
-  onTertiary: Color(0xFF042433),
-  surface: _surface,
+  primary: _primary,
+  onPrimary: Color(0xFF002F64),
+  secondary: Color(0xFFAEC7F6),
+  tertiary: _referenceOrange,
+  onTertiary: Color(0xFF532200),
+  surface: _surfaceMid,
   onSurface: _ink,
-  surfaceContainerHighest: Color(0xFF262220),
-  onSurfaceVariant: _ink,
+  surfaceContainerHighest: Color(0xFF353534),
+  onSurfaceVariant: Color(0xFFC1C6D5),
   outline: _outline,
   error: _danger,
-  onError: _ink,
+  onError: Color(0xFF690005),
 );
 
 /// The near-black ground the whole app sits on.
 const ripprBackground = _ground;
 
+/// Cards and modals — one step up from [ripprColors]'s `surface`, per the design
+/// system's three-level stack ("Surface Strategy": base darkest, cards a step lighter).
+/// Exposed separately because `ColorScheme` has no fourth surface slot for it that isn't
+/// already claimed by `surfaceContainerHighest` (reserved here for the selected/
+/// highlighted state, not the resting card colour).
+const ripprCardColor = Color(0xFF16161A);
+
+/// Shape spec: "Rounded (Level 2)" — small components (buttons, inputs) get 8px, large
+/// containers (cards, modals) get 16px. Two constants, not a single "roundness" figure,
+/// because the spec explicitly gives them different values.
+const double ripprRadiusSmall = 8.0;
+const double ripprRadiusLarge = 16.0;
+
 ThemeData ripprTheme() {
   final base = ThemeData(
     colorScheme: ripprColors,
@@ -57,13 +85,25 @@ ThemeData ripprTheme() {
     // Flutter's equivalent exposure is the default text colour. Setting it explicitly
     // here, rather than relying on a wrapping widget, means the failure cannot recur by
     // someone removing a container.
+    // UI-08: the design system specifies Inter exclusively. Not switched to here --
+    // naming a fontFamily with no matching asset bundled would silently fall back to
+    // the platform default (Roboto), the exact class of invisible failure the bodyColor
+    // fix below exists to prevent. Bundling the actual font files (or a vetted offline
+    // build of the google_fonts package) is left as a deliberate follow-up rather than
+    // shipping a fontFamily string that doesn't resolve to anything.
     textTheme: base.textTheme.apply(bodyColor: _ink, displayColor: _ink),
     appBarTheme: const AppBarTheme(
       backgroundColor: _ground,
       foregroundColor: _ink,
       elevation: 0,
     ),
-    dividerTheme: const DividerThemeData(color: Color(0xFF322C28), space: 1),
+    cardTheme: const CardThemeData(
+      color: ripprCardColor,
+      shape: RoundedRectangleBorder(
+        borderRadius: BorderRadius.all(Radius.circular(ripprRadiusLarge)),
+      ),
+    ),
+    dividerTheme: const DividerThemeData(color: Color(0xFF2D3037), space: 1),
   );
 }