Hi Alison Schuster,
Could you please provide us your site url and link of pages where you want to change the size and color of link. So we can provide your appropriate solution.
Or you can add this following css on child theme style.css or “Additional css section” of customizer. It might help you on this:
body a {
color: red;
font-size: 12px;
}
Note: Please change the color and font-size value as per your requirement. This css would change link color and size on your whole website.
Thanks