Function handler

web/lib/theme.tsx:50–50

(e: MediaQueryListEvent)

      const mq = window.matchMedia('(prefers-color-scheme: light)')
      apply(mq.matches ? 'light' : 'dark')
      const handler = (e: MediaQueryListEvent) => apply(e.matches ? 'light' : 'dark')
      mq.addEventListener('change', handler)
      return () => mq.removeEventListener('change', handler)
    } else {