text-emphasis-color: currentColor;

text-emphasis-color: red;

text-emphasis-color: rgb(90 200 160 / 0.8);

<section id="default-example">
  <p>
    I'd far rather be
    <span class="transition-all" id="example-element">happy than right</span>
    any day.
  </p>
</section>

p {
  font: 1.5em sans-serif;
}

#example-element {
  text-emphasis: filled;
}

/* Initial value */
text-emphasis-color: currentColor;

/* <color> */
text-emphasis-color: #555555;
text-emphasis-color: blue;
text-emphasis-color: rgb(90 200 160 / 80%);
text-emphasis-color: transparent;

/* Global values */
text-emphasis-color: inherit;
text-emphasis-color: initial;
text-emphasis-color: revert;
text-emphasis-color: revert-layer;
text-emphasis-color: unset;

em {
  text-emphasis-color: green;
  text-emphasis-style: "*";
}

<p>Here's an example:</p>

<em>This has emphasis marks!</em>