08Split text mask reveal

<main class="stage is-demo">
  <div class="headline">
    <h1 class="headline__mask">Type less. Ship more.</h1>
    <span class="headline__underline" aria-hidden="true"></span>
  </div>
</main>

@use "../../../../site/static/demo-tokens" as *;

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;   // 2s — 리빌·홀드·리셋 한 바퀴
$easing: $ease-spring;
$color: $subject-ink;

@include stage($stage-paper);

.headline {
  margin: 0;
  box-sizing: border-box;
  max-width: clamp(220px, 80vw, 380px);
  text-align: center;
}

// clip-path 를 애니메이션 대상으로 쓴다 — blog-demo 규칙 1(transform·opacity 만)의 의도적 예외.
// 마스크 리빌(왼쪽→오른쪽으로 쓸려 나오는 등장)은 clip-path 없이는 표현이 안 된다 (사실.md 기록)
.headline__mask {
  display: inline-block;
  margin: 0;
  color: $color;
  font-weight: 800;
  font-size: clamp(20px, 6.4vw, 30px);
  line-height: 1.3;
  font-family: inherit;
  clip-path: inset(0 100% 0 0);
}

.headline__underline {
  display: block;
  margin: $sp-2 auto 0;
  width: 64px;
  height: 3px;
  background: #c78da8;
  transform: scaleX(0);
  transform-origin: left center; // 규칙8: 언더라인 left 그어짐
}

.stage.is-demo .headline__mask { animation: reveal $duration $easing infinite; }
.stage.is-demo .headline__underline { animation: underline-grow $duration $easing infinite; }

@keyframes reveal {
  0%   { clip-path: inset(0 100% 0 0); }
  40%  { clip-path: inset(0 0% 0 0); }
  85%  { clip-path: inset(0 0% 0 0); }
  100% { clip-path: inset(0 100% 0 0); }
}

@keyframes underline-grow {
  0%   { transform: scaleX(0); }
  40%  { transform: scaleX(1); }
  85%  { transform: scaleX(1); }
  100% { transform: scaleX(0); }
}

@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .headline__mask { animation: none; clip-path: inset(0 0% 0 0); }
  .stage.is-demo .headline__underline { animation: none; transform: scaleX(1); }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffffff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.headline {
  margin: 0;
  box-sizing: border-box;
  max-width: clamp(220px, 80vw, 380px);
  text-align: center;
}

.headline__mask {
  display: inline-block;
  margin: 0;
  color: #17141a;
  font-weight: 800;
  font-size: clamp(20px, 6.4vw, 30px);
  line-height: 1.3;
  font-family: inherit;
  clip-path: inset(0 100% 0 0);
}

.headline__underline {
  display: block;
  margin: 8px auto 0;
  width: 64px;
  height: 3px;
  background: #c78da8;
  transform: scaleX(0);
  transform-origin: left center;
}

.stage.is-demo .headline__mask {
  animation: reveal 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.stage.is-demo .headline__underline {
  animation: underline-grow 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@keyframes reveal {
  0% {
    clip-path: inset(0 100% 0 0);
  }
  40% {
    clip-path: inset(0 0% 0 0);
  }
  85% {
    clip-path: inset(0 0% 0 0);
  }
  100% {
    clip-path: inset(0 100% 0 0);
  }
}
@keyframes underline-grow {
  0% {
    transform: scaleX(0);
  }
  40% {
    transform: scaleX(1);
  }
  85% {
    transform: scaleX(1);
  }
  100% {
    transform: scaleX(0);
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .headline__mask {
    animation: none;
    clip-path: inset(0 0% 0 0);
  }
  .stage.is-demo .headline__underline {
    animation: none;
    transform: scaleX(1);
  }
}

import type { CSSProperties } from "react";
import styles from "./SplitTextMaskReveal.module.scss";

export type SplitTextMaskRevealProps = {
  text?: string;
  duration?: number;
  easing?: string;
  color?: string;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };

export default function SplitTextMaskReveal({
  text = "Type less. Ship more.",
  duration = 2000,
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#17141a",
}: SplitTextMaskRevealProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  return (
    <div className={styles.headline} style={vars}>
      <h1 className={styles.mask}>{text}</h1>
      <span className={styles.underline} aria-hidden="true" />
    </div>
  );
}