01Headline stagger in

<main class="stage is-demo">
  <h1 class="hero">
    <span class="hero__line hero__line--1">Ship your idea.</span>
    <span class="hero__line hero__line--2">Faster than ever.</span>
    <span class="hero__line hero__line--3">Start <em>free</em> today.</span>
  </h1>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;   // 2s — 3줄이 순차 등장하는 한 바퀴
$easing: $ease-spring;
$color: $subject-cream;

@include stage($stage-ink);

.hero {
  margin: 0;
  box-sizing: border-box;
  max-width: clamp(220px, 78vw, 360px);
  text-align: center;
  display: grid;
  gap: $sp-2;
}

.hero__line {
  display: block;
  font-weight: 800;
  font-size: clamp(18px, 6vw, 28px);
  line-height: 1.28;
  font-family: inherit;
  color: $color;
  letter-spacing: -0.01em;
  opacity: 0;
  transform: translateY($sp-6);
}

.hero__line--3 em { font-style: normal; color: #beab7c; }

.stage.is-demo .hero__line--1 { animation: line-in-1 $duration $easing infinite; }
.stage.is-demo .hero__line--2 { animation: line-in-2 $duration $easing infinite; }
.stage.is-demo .hero__line--3 { animation: line-in-3 $duration $easing infinite; }

@keyframes line-in-1 {
  0%   { opacity: 0; transform: translateY($sp-6); }
  10%  { opacity: 1; transform: translateY(0); }
  85%  { opacity: 1; transform: translateY(0); }
  100% { opacity: 0; transform: translateY($sp-6); }
}

@keyframes line-in-2 {
  0%, 10% { opacity: 0; transform: translateY($sp-6); }
  20%     { opacity: 1; transform: translateY(0); }
  85%     { opacity: 1; transform: translateY(0); }
  100%    { opacity: 0; transform: translateY($sp-6); }
}

@keyframes line-in-3 {
  0%, 20% { opacity: 0; transform: translateY($sp-6); }
  30%     { opacity: 1; transform: translateY(0); }
  85%     { opacity: 1; transform: translateY(0); }
  100%    { opacity: 0; transform: translateY($sp-6); }
}

@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .hero__line--1,
  .stage.is-demo .hero__line--2,
  .stage.is-demo .hero__line--3 {
    animation: none;
    opacity: 1;
    transform: none;
  }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.hero {
  margin: 0;
  box-sizing: border-box;
  max-width: clamp(220px, 78vw, 360px);
  text-align: center;
  display: grid;
  gap: 8px;
}

.hero__line {
  display: block;
  font-weight: 800;
  font-size: clamp(18px, 6vw, 28px);
  line-height: 1.28;
  font-family: inherit;
  color: #fff7e6;
  letter-spacing: -0.01em;
  opacity: 0;
  transform: translateY(24px);
}

.hero__line--3 em {
  font-style: normal;
  color: #beab7c;
}

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

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

.stage.is-demo .hero__line--3 {
  animation: line-in-3 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@keyframes line-in-1 {
  0% {
    opacity: 0;
    transform: translateY(24px);
  }
  10% {
    opacity: 1;
    transform: translateY(0);
  }
  85% {
    opacity: 1;
    transform: translateY(0);
  }
  100% {
    opacity: 0;
    transform: translateY(24px);
  }
}
@keyframes line-in-2 {
  0%, 10% {
    opacity: 0;
    transform: translateY(24px);
  }
  20% {
    opacity: 1;
    transform: translateY(0);
  }
  85% {
    opacity: 1;
    transform: translateY(0);
  }
  100% {
    opacity: 0;
    transform: translateY(24px);
  }
}
@keyframes line-in-3 {
  0%, 20% {
    opacity: 0;
    transform: translateY(24px);
  }
  30% {
    opacity: 1;
    transform: translateY(0);
  }
  85% {
    opacity: 1;
    transform: translateY(0);
  }
  100% {
    opacity: 0;
    transform: translateY(24px);
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .hero__line--1,
  .stage.is-demo .hero__line--2,
  .stage.is-demo .hero__line--3 {
    animation: none;
    opacity: 1;
    transform: none;
  }
}

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

export type HeadlineStaggerInProps = {
  lines?: [string, string, string];
  duration?: number;
  easing?: string;
  color?: string;
};

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

export default function HeadlineStaggerIn({
  lines = ["Ship your idea.", "Faster than ever.", "Start free today."],
  duration = 2000,
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#fff7e6",
}: HeadlineStaggerInProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  return (
    <h1 className={styles.hero} style={vars}>
      <span className={`${styles.line} ${styles.line1}`}>{lines[0]}</span>
      <span className={`${styles.line} ${styles.line2}`}>{lines[1]}</span>
      <span className={`${styles.line} ${styles.line3}`}>{lines[2]}</span>
    </h1>
  );
}