Task 20: Accessibility audit improvements

Semantic HTML:
- Changed Card component from div to article element
- Added id="main-content" to main element for skip link target

Keyboard Navigation & ARIA:
- Added skip link to TopBar (visible only on focus, navigates to #main-content)
- Added aria-label="Active session information" to session info container
- Added aria-hidden="true" to all decorative colored dots (CardHeader, CareerActivity, Projects, Sidebar status badge)
- All expandable items already have role="button", tabIndex={0}, aria-expanded
- All KPI cards already have proper aria-label describing flip state
- Command palette already has full ARIA implementation (combobox, listbox, dialog)

Focus Management:
- Added global focus-visible styles in index.css (2px accent outline, 2px offset)
- Buttons, links, inputs all have proper focus rings with accent color
- Command palette focus trap already implemented

Reduced Motion:
- All components already check prefers-reduced-motion at module scope
- Dashboard entrance, tile expansion, KPI flip, palette animations respect reduced motion
- Added reduced motion override for pulse animation (disables pulse, keeps static dot)

Color Contrast:
- All color tokens already meet WCAG AA standards per ref spec
- Tertiary text (#8DA8A5) used only for supplementary labels where information is conveyed elsewhere

Quality checks: typecheck ✓, lint ✓ (1 pre-existing warning), build ✓

src/components/Card.tsx

@@ -23,7 +23,7 @@ export function Card({ children, full, className, tileId }: CardProps) {
   }
 
   return (
-    <div
+    <article
       style={baseStyles}
       className={className}
       data-tile-id={tileId}
@@ -31,7 +31,7 @@ export function Card({ children, full, className, tileId }: CardProps) {
       onMouseLeave={() => setIsHovered(false)}
     >
       {children}
-    </div>
+    </article>
   )
 }
 
@@ -85,7 +85,7 @@ export function CardHeader({ dotColor, title, rightText }: CardHeaderProps) {
 
   return (
     <div style={headerStyles}>
-      <div style={dotStyles} />
+      <div style={dotStyles} aria-hidden="true" />
       <span style={titleStyles}>{title}</span>
       {rightText && <span style={rightTextStyles}>{rightText}</span>}
     </div>

src/components/DashboardLayout.tsx

@@ -135,6 +135,7 @@ export function DashboardLayout() {
 
         {/* Main content — scrollable card grid */}
         <motion.main
+          id="main-content"
           initial="hidden"
           animate="visible"
           variants={contentVariants}

src/components/Sidebar.tsx

@@ -219,6 +219,7 @@ export default function Sidebar() {
               background: 'var(--success)',
               animation: 'pulse 2s infinite',
             }}
+            aria-hidden="true"
           />
           <span>{patient.badge}</span>
         </div>

src/components/TopBar.tsx

@@ -26,6 +26,32 @@ export function TopBar({ onSearchClick }: TopBarProps) {
         zIndex: 100,
       }}
     >
+      {/* Skip to main content link (only visible on focus) */}
+      <a
+        href="#main-content"
+        className="skip-link"
+        style={{
+          position: 'absolute',
+          top: '-40px',
+          left: '0',
+          background: 'var(--accent)',
+          color: '#FFFFFF',
+          padding: '8px 16px',
+          textDecoration: 'none',
+          zIndex: 101,
+          borderRadius: '0 0 4px 0',
+          fontSize: '13px',
+          fontWeight: 600,
+        }}
+        onFocus={(e) => {
+          e.currentTarget.style.top = '0'
+        }}
+        onBlur={(e) => {
+          e.currentTarget.style.top = '-40px'
+        }}
+      >
+        Skip to main content
+      </a>
       {/* Brand */}
       <div className="flex items-center gap-2 shrink-0">
         <Home
@@ -131,7 +157,10 @@ export function TopBar({ onSearchClick }: TopBarProps) {
       </button>
 
       {/* Session info (right) */}
-      <div className="flex items-center gap-2 sm:gap-3 shrink-0">
+      <div
+        className="flex items-center gap-2 sm:gap-3 shrink-0"
+        aria-label="Active session information"
+      >
         <span
           className="hidden sm:inline"
           style={{

src/components/tiles/CareerActivityTile.tsx

@@ -218,6 +218,7 @@ const ActivityItem: React.FC<ActivityItemProps> = ({ entry, isExpanded, onToggle
             flexShrink: 0,
             marginTop: '2px',
           }}
+          aria-hidden="true"
         />
         <div style={{ flex: 1, minWidth: 0 }}>
           <div

src/components/tiles/ProjectsTile.tsx

@@ -85,6 +85,7 @@ function ProjectItem({ project, isExpanded, onToggle }: ProjectItemProps) {
             marginTop: '4px',
             animation: isLive ? 'pulse 2s infinite' : undefined,
           }}
+          aria-hidden="true"
         />
         <span style={{ flex: 1 }}>{project.name}</span>
         <span