Task 4b: Fix PatientBanner scroll condensation

Root cause: sentinel element with `absolute top-0` inside PatientBanner was
positioned at viewport top, always triggering the IntersectionObserver's
-100px rootMargin threshold — banner was permanently stuck in condensed state.

Fix: Restructured PMRInterface layout from document-scroll to flex container
with explicit scroll container (`overflow-y-auto` on main). Lifted scroll
condensation logic to PMRInterface, passing `isCondensed` prop down to
PatientBanner. Replaced IntersectionObserver with scroll event listener on
the main element for reliable scroll position detection.

Key changes:
- PMRInterface: flex h-screen overflow-hidden layout (sidebar + content column)
- PatientBanner: accepts isCondensed prop, removed sticky/sentinel/hook
- ClinicalSidebar: h-full instead of h-screen sticky (parent handles sizing)
- useScrollCondensation: scroll event on container element via callback ref

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/ClinicalSidebar.tsx

@@ -168,7 +168,7 @@ export function ClinicalSidebar({ activeView, onViewChange, isTablet = false }:
       <aside
         role="navigation"
         aria-label="Clinical record navigation"
-        className="hidden md:flex lg:hidden flex-col w-14 h-screen sticky top-0 bg-pmr-sidebar text-white"
+        className="hidden md:flex lg:hidden flex-col w-14 h-full bg-pmr-sidebar text-white"
       >
         <div className="p-2 border-b border-white/10">
           <div className="font-inter font-medium text-[10px] text-white/50 text-center leading-tight">
@@ -230,7 +230,7 @@ export function ClinicalSidebar({ activeView, onViewChange, isTablet = false }:
     <aside
       role="navigation"
       aria-label="Clinical record navigation"
-      className="hidden lg:flex flex-col w-[220px] h-screen sticky top-0 bg-pmr-sidebar text-white"
+      className="hidden lg:flex flex-col w-[220px] h-full bg-pmr-sidebar text-white"
     >
       <div className="p-4 border-b border-white/10">
         <div className="font-inter font-medium text-[13px] text-white/50 leading-tight">

src/components/PMRInterface.tsx

@@ -1,4 +1,4 @@
-import { useState, useEffect, useRef, useMemo } from 'react'
+import { useState, useEffect, useRef, useMemo, useCallback } from 'react'
 import { motion, Variants } from 'framer-motion'
 import { Search, X, ArrowLeft } from 'lucide-react'
 import type { ViewId } from '../types/pmr'
@@ -14,6 +14,7 @@ import { DocumentsView } from './views/DocumentsView'
 import { ReferralsView } from './views/ReferralsView'
 import { useAccessibility } from '../contexts/AccessibilityContext'
 import { useBreakpoint } from '../hooks/useBreakpoint'
+import { useScrollCondensation } from '../hooks/useScrollCondensation'
 
 interface PMRInterfaceProps {
   children?: React.ReactNode
@@ -37,8 +38,13 @@ function PMRContent({ children }: PMRInterfaceProps) {
   const [mobileSearchQuery, setMobileSearchQuery] = useState('')
   
   const viewHeadingRef = useRef<HTMLDivElement>(null)
+  const [scrollContainer, setScrollContainer] = useState<HTMLElement | null>(null)
+  const scrollContainerCallbackRef = useCallback((node: HTMLElement | null) => {
+    setScrollContainer(node)
+  }, [])
   const { requestFocusAfterViewChange, expandedItemId, setExpandedItem } = useAccessibility()
   const { isMobile, isTablet } = useBreakpoint()
+  const { isCondensed } = useScrollCondensation({ threshold: 100, scrollContainer })
 
   const prefersReducedMotion = typeof window !== 'undefined' 
     ? window.matchMedia('(prefers-reduced-motion: reduce)').matches 
@@ -148,31 +154,35 @@ function PMRContent({ children }: PMRInterfaceProps) {
 
   return (
     <motion.div
-      className="min-h-screen bg-pmr-content"
+      className="flex h-screen overflow-hidden bg-pmr-content"
       initial="hidden"
       animate="visible"
     >
-      <motion.div variants={bannerVariants}>
+      {/* Fixed sidebar */}
-        <PatientBanner isMobile={isMobile} isTablet={isTablet} />
+      {!isMobile && (
-      </motion.div>
+        <motion.div variants={sidebarVariants} className="flex-shrink-0">
-      <div className="flex">
+          <ClinicalSidebar
-        {!isMobile && (
+            activeView={activeView}
-          <motion.div variants={sidebarVariants}>
+            onViewChange={handleViewChange}
-            <ClinicalSidebar 
+            isTablet={isTablet}
-              activeView={activeView} 
+          />
-              onViewChange={handleViewChange}
+        </motion.div>
-              isTablet={isTablet}
+      )}
-            />
+
-          </motion.div>
+      {/* Main content column: banner (fixed) + scrollable content */}
-        )}
+      <div className="flex-1 flex flex-col min-w-0">
+        <motion.div variants={bannerVariants} className="flex-shrink-0">
+          <PatientBanner isMobile={isMobile} isTablet={isTablet} isCondensed={isCondensed} />
+        </motion.div>
+
         <motion.main
+          ref={scrollContainerCallbackRef}
           variants={contentVariants}
           role="main"
           aria-label={`${activeView} view`}
           className={`
-            flex-1 p-4 md:p-6
+            flex-1 overflow-y-auto p-4 md:p-6
             ${isMobile ? 'pb-20' : ''}
-            ${isTablet ? 'min-h-[calc(100vh-48px)]' : 'min-h-[calc(100vh-80px)]'}
           `}
         >
           {isMobile && (

src/components/PatientBanner.tsx

@@ -2,79 +2,61 @@ import { Download, Mail, Linkedin, MoreHorizontal } from 'lucide-react'
 import { useState, useRef, useEffect, useCallback } from 'react'
 import { motion, AnimatePresence } from 'framer-motion'
 import { patient } from '@/data/patient'
-import { useScrollCondensation } from '@/hooks/useScrollCondensation'
 
 interface PatientBannerProps {
   isMobile?: boolean
   isTablet?: boolean
+  isCondensed?: boolean
 }
 
-export function PatientBanner({ isMobile = false, isTablet = false }: PatientBannerProps) {
+export function PatientBanner({ isMobile = false, isTablet = false, isCondensed = false }: PatientBannerProps) {
-  const { isCondensed, sentinelRef } = useScrollCondensation({ threshold: 100 })
-
   const prefersReducedMotion = typeof window !== 'undefined'
     ? window.matchMedia('(prefers-reduced-motion: reduce)').matches
     : false
 
   if (isMobile) {
-    return (
+    return <MobileBanner />
-      <>
-        <div
-          ref={sentinelRef}
-          className="h-0 w-full absolute top-0"
-          aria-hidden="true"
-        />
-        <MobileBanner />
-      </>
-    )
   }
 
   const shouldCondense = isTablet || isCondensed
 
   return (
-    <>
+    <header
-      <div
+      className={`
-        ref={sentinelRef}
+        w-full z-40
-        className="h-0 w-full absolute top-0"
+        bg-pmr-banner border-b border-slate-600
-        aria-hidden="true"
+        shadow-pmr-banner
-      />
+        transition-all duration-200 ease-out
-      <header
+        ${shouldCondense ? 'h-12' : 'h-20'}
-        className={`
+      `}
-          sticky top-0 z-40 w-full
+      role="banner"
-          bg-pmr-banner border-b border-slate-600
+    >
-          shadow-pmr-banner
+      <AnimatePresence mode="wait" initial={false}>
-          transition-all duration-200 ease-out
+        {shouldCondense ? (
-          ${shouldCondense ? 'h-12' : 'h-20'}
+          <motion.div
-        `}
+            key="condensed"
-        role="banner"
+            initial={prefersReducedMotion ? false : { opacity: 0 }}
-      >
+            animate={{ opacity: 1 }}
-        <AnimatePresence mode="wait" initial={false}>
+            exit={prefersReducedMotion ? undefined : { opacity: 0 }}
-          {shouldCondense ? (
+            transition={{ duration: 0.15 }}
-            <motion.div
+            className="h-full"
-              key="condensed"
+          >
-              initial={prefersReducedMotion ? false : { opacity: 0 }}
+            <CondensedBanner />
-              animate={{ opacity: 1 }}
+          </motion.div>
-              exit={prefersReducedMotion ? undefined : { opacity: 0 }}
+        ) : (
-              transition={{ duration: 0.15 }}
+          <motion.div
-              className="h-full"
+            key="full"
-            >
+            initial={prefersReducedMotion ? false : { opacity: 0 }}
-              <CondensedBanner />
+            animate={{ opacity: 1 }}
-            </motion.div>
+            exit={prefersReducedMotion ? undefined : { opacity: 0 }}
-          ) : (
+            transition={{ duration: 0.15 }}
-            <motion.div
+            className="h-full"
-              key="full"
+          >
-              initial={prefersReducedMotion ? false : { opacity: 0 }}
+            <FullBanner />
-              animate={{ opacity: 1 }}
+          </motion.div>
-              exit={prefersReducedMotion ? undefined : { opacity: 0 }}
+        )}
-              transition={{ duration: 0.15 }}
+      </AnimatePresence>
-              className="h-full"
+    </header>
-            >
-              <FullBanner />
-            </motion.div>
-          )}
-        </AnimatePresence>
-      </header>
-    </>
   )
 }
 
@@ -97,7 +79,7 @@ function MobileBanner() {
 
   return (
     <header
-      className="sticky top-0 z-40 w-full h-12 bg-pmr-banner border-b border-slate-600 shadow-pmr-banner"
+      className="w-full z-40 h-12 bg-pmr-banner border-b border-slate-600 shadow-pmr-banner"
       role="banner"
     >
       <div className="h-full px-3 flex items-center justify-between gap-2">

src/hooks/useScrollCondensation.ts

@@ -1,35 +1,30 @@
-import { useState, useEffect, useRef } from 'react'
+import { useState, useEffect, useCallback } from 'react'
 
 interface UseScrollCondensationOptions {
   threshold?: number
+  scrollContainer?: HTMLElement | null
 }
 
 export function useScrollCondensation(options: UseScrollCondensationOptions = {}) {
-  const { threshold = 100 } = options
+  const { threshold = 100, scrollContainer } = options
   const [isCondensed, setIsCondensed] = useState(false)
-  const sentinelRef = useRef<HTMLDivElement>(null)
+
+  const handleScroll = useCallback(() => {
+    if (!scrollContainer) return
+    setIsCondensed(scrollContainer.scrollTop >= threshold)
+  }, [scrollContainer, threshold])
 
   useEffect(() => {
-    const sentinel = sentinelRef.current
+    if (!scrollContainer) return
-    if (!sentinel) return
 
-    const observer = new IntersectionObserver(
+    scrollContainer.addEventListener('scroll', handleScroll, { passive: true })
-      (entries) => {
+    // Check initial state
-        const [entry] = entries
+    handleScroll()
-        setIsCondensed(!entry.isIntersecting)
-      },
-      {
-        rootMargin: `-${threshold}px 0px 0px 0px`,
-        threshold: 0,
-      }
-    )
-
-    observer.observe(sentinel)
 
     return () => {
-      observer.disconnect()
+      scrollContainer.removeEventListener('scroll', handleScroll)
     }
-  }, [threshold])
+  }, [scrollContainer, handleScroll])
 
-  return { isCondensed, sentinelRef }
+  return { isCondensed }
 }