CSS 라이브 데모: text-decoration-style 데모 버튼을 클릭해 보세요!
selector {
    text-decoration-style: solid | double | dotted | dashed | wavy
}
/* 키워드 값 */
text-decoration-style: solid;
text-decoration-style: double;
text-decoration-style: dotted;
text-decoration-style: dashed;
text-decoration-style: wavy;

/* 전역 값 */
text-decoration-style: inherit;
text-decoration-style: initial;
text-decoration-style: revert;
text-decoration-style: revert-layer;
text-decoration-style: unset;
<p>텍스트 데코레이션 스타일 값이 wavy입니다.</p>
p {
    text-decoration: underline;
    text-decoration-color: red;
    text-decoration-style: wavy;
}
실제 적용 모습