feat: US-016 - Apply chosen parent header typography

Elvaro Grotesque 600, -0.02em tracking with responsive scale from
1.375rem (mobile) to 2.2rem (desktop). Refined from the baseline
700/2.4rem for a more premium, intentional feel.

Ralph/prd.json

@@ -285,8 +285,8 @@
         "Verify in browser using dev-browser skill"
       ],
       "priority": 16,
-      "passes": false,
-      "notes": "Depends on US-015 having selected a font treatment. Apply it consistently to ParentSection.tsx."
+      "passes": true,
+      "notes": "Applied Elvaro Grotesque 600, -0.02em tracking with responsive scale: 1.375rem (mobile) → 1.6rem (sm) → 1.8rem (md) → 2.2rem (lg). Both headers identical. Verified at 375px (22px) and 1024px+ (35.2px)."
     },
     {
       "id": "US-017",

Ralph/progress.txt

@@ -1102,3 +1102,25 @@ Visual exploration of parent section header typography. Tested 14 combinations i
 - Teal-colored headers compete with KPI accent values — parent headers should stay in text-primary
 - Tight negative tracking (-0.02em to -0.03em) consistently improves the premium feel at heading sizes
 ---
+
+## Iteration 16 — US-016: Apply chosen parent header typography
+**Status**: PASS
+**Commit**: (this iteration)
+
+### What was done
+Applied the selected typography from US-015 to ParentSection.tsx:
+- **Font**: Elvaro Grotesque (unchanged — consistent with body)
+- **Weight**: 600 (down from 700)
+- **Letter-spacing**: -0.02em (tight tracking)
+- **Responsive scale**: `1.375rem` → `1.6rem` (sm) → `1.8rem` (md) → `2.2rem` (lg)
+  - Previous: `1.5rem` → `1.8rem` → `2rem` → `2.4rem`
+
+### Changes
+- **ParentSection.tsx**: Updated h2 className responsive sizes and inline style (fontWeight 700→600, added letterSpacing -0.02em)
+
+### Verification
+- **Desktop (1024px+)**: 35.2px / 600 weight / -0.704px tracking — refined, premium feel
+- **Mobile (375px)**: 22px / 600 weight — proportional, readable
+- Both "Patient Summary" and "Patient Pathway" headers identical
+- Clear hierarchy: parent headers (2.2rem/600) > sub-headers (12px/600 uppercase) > body (13px/400)
+---

src/components/ParentSection.tsx

@@ -12,9 +12,10 @@ export function ParentSection({ title, children, className, tileId }: ParentSect
   return (
     <Card full className={className} tileId={tileId}>
       <h2
-        className="text-[1.5rem] sm:text-[1.8rem] md:text-[2rem] lg:text-[2.4rem]"
+        className="text-[1.375rem] sm:text-[1.6rem] md:text-[1.8rem] lg:text-[2.2rem]"
         style={{
-          fontWeight: 700,
+          fontWeight: 600,
+          letterSpacing: '-0.02em',
           color: 'var(--text-primary)',
           lineHeight: 1.1,
           margin: 0,