fix(a11y): increase contrast

frontend/src/lib/components/PdfViewer.svelte

@@ -325,7 +325,7 @@ function zoomOut() {
 				</button>
 
 				{#if totalPages > 0}
-					<span class="font-sans text-xs text-ink-3 tabular-nums">
+					<span class="font-sans text-xs text-ink-2 tabular-nums">
 						{currentPage} / {totalPages}
 					</span>
 				{/if}
@@ -394,7 +394,7 @@ function zoomOut() {
 					onclick={() => (showAnnotations = !showAnnotations)}
 					aria-label={showAnnotations ? m.pdf_annotations_hide() : m.pdf_annotations_show()}
 					class="flex items-center gap-1.5 rounded px-2 py-1 font-sans text-xs transition {showAnnotations
-						? 'text-ink-3 hover:bg-surface/10'
+						? 'text-ink-2 hover:bg-surface/10'
 						: 'bg-surface/10 text-accent'}"
 				>
 					<svg