Replace remaining hardcoded hex colors with color tokens (CR-27)

Map leftover component hex values onto the existing color scale, and leave third-party share brands and the Avatar white-alpha border documented as intentional exceptions.

app/components/sections/Accordion/Accordion.view.tsx

@@ -20,7 +20,7 @@ function FaqAccordionView({
   return (
     <section
       aria-labelledby={headingId}
-      className={`bg-[#141414] px-[var(--spacing-scale-004)] py-[var(--spacing-scale-032)] md:px-[var(--spacing-scale-160)] md:py-[var(--spacing-scale-096)] ${className}`.trim()}
+      className={`bg-[var(--color-surface-default-secondary)] px-[var(--spacing-scale-004)] py-[var(--spacing-scale-032)] md:px-[var(--spacing-scale-160)] md:py-[var(--spacing-scale-096)] ${className}`.trim()}
     >
       <div className="mx-auto flex w-full max-w-[1440px] flex-col items-center gap-[var(--spacing-scale-096)] md:gap-[var(--spacing-scale-040)]">
         <h2