Lorem ipsum dolor sit amet consectetur adipisicing elit. Provident quod non  <span  style="--internal-link-color: green"><a class="internal-link">iusto illo dolorum</a></span> est mollitia pariatur repellendus <a class="internal-link">officia porro</a>, repudiandae debitis ut cumque blanditiis eum! Eius fugiat laboriosam illum.

:root {
  --internal-link-color: red;
}

body {
  margin: 0;
  font-size: 20px;
}

.internal-link {
  color: var(--internal-link-color);
  text-decoration: underline;
}