text-decoration-line

text-decoration-line: none;

text-decoration-line: underline;

text-decoration-line: overline;

text-decoration-line: line-through;

text-decoration-line: underline overline;

text-decoration-line: underline line-through;

<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;
}

/* 単一のキーワード */
text-decoration-line: none;
text-decoration-line: underline;
text-decoration-line: overline;
text-decoration-line: line-through;
text-decoration-line: blink;
/* 複数のキーワード */
text-decoration-line: underline overline; /* 2 本の装飾線 */
text-decoration-line: overline underline line-through; /* 複数の装飾線 */
/* グローバル値 */
text-decoration-line: inherit;
text-decoration-line: initial;
text-decoration-line: revert;
text-decoration-line: revert-layer;
text-decoration-line: unset;

<p class="wavy">こちらのテキストには赤い波線の下線が付いています。</p>
<p class="both">このテキストには上線と下線がついています。</p>

.wavy {
  text-decoration-line: underline;
  text-decoration-style: wavy;
  text-decoration-color: red;
}
.both {
  text-decoration-line: underline overline;
}