next.js/examples/amp/components/Layout.tsx

type LayoutProps = {
  children?: React.ReactNode;
};

export default function Layout({ children }: LayoutProps) {
  return (
    <>
      {children}
      <style jsx global>{`
        body {
          font-family: Roboto, sans-serif;
          padding: 30px;
          color: #444;
        }
      `}</style>
    </>
  );
}