07Vẽ đường tiến trình theo scroll(scroll())

<main class="stage">
  <div class="ts07-box">
    <span class="ts07-rail is-demo"></span>
    <div class="ts07-content">
      <div class="ts07-item">09:00</div>
      <div class="ts07-item">09:20</div>
      <div class="ts07-item">10:00</div>
      <div class="ts07-item">10:40</div>
      <div class="ts07-item">11:10</div>
    </div>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;
$easing: linear;
$color: $subject-ink;   // 주황 무대 위 전경은 잉크 — 크림은 3.11:1

@include stage($stage-orange);

.ts07-box {
  position: relative;
  width: min(220px, 80vw);
  height: clamp(120px, 62vh, 200px);
  overflow-y: auto;
  padding: $sp-2 0 $sp-2 $sp-6;
  box-sizing: border-box;
  background: rgba(255, 247, 230, .25);   // 잉크 글자를 받는 상자 — 먹 틴트(4.32:1) 대신 크림 틴트 6.98:1
  border-radius: $r-sm;
}

.ts07-content { position: relative; }

.ts07-rail {
  position: absolute;
  left: $sp-2;
  top: 0;
  width: 3px;
  height: 100%;
  background: $color;
  border-radius: $r-xs;
  transform-origin: top; // 규칙8: 스크롤 진행선 위 기준 채움
  transform: scaleY(0);
}

// 실제 사용 코드: 상자를 안에서 스크롤하면 JS 없이 진행률만큼 그려진다
@supports (animation-timeline: scroll()) {
  .ts07-rail:not(.is-demo) {
    animation: ts07-draw linear both;
    animation-timeline: scroll(nearest block);
  }
}
// 미지원 브라우저(Firefox·Safari): 다 그려진 최종 상태로 고정
@supports not (animation-timeline: scroll()) {
  .ts07-rail:not(.is-demo) { transform: scaleY(1); }
}

@keyframes ts07-draw { from { transform: scaleY(0); } to { transform: scaleY(1); } }

.ts07-item {
  padding: $sp-2 0;
  color: $color;
  font: 600 13px/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  border-bottom: 1px solid rgba(23, 20, 26, .14);
}

// 데모 루프: 실제 스크롤 대신 2초 주기로 진행률을 흉내(캡처용)
.ts07-rail.is-demo { animation: ts07-draw-loop $duration $easing infinite; }
@keyframes ts07-draw-loop { 0% { transform: scaleY(0); } 100% { transform: scaleY(1); } }

@media (prefers-reduced-motion: reduce) {
  .ts07-rail, .ts07-rail.is-demo { animation: none !important; transform: scaleY(1) !important; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.ts07-box {
  position: relative;
  width: min(220px, 80vw);
  height: clamp(120px, 62vh, 200px);
  overflow-y: auto;
  padding: 8px 0 8px 24px;
  box-sizing: border-box;
  background: rgba(255, 247, 230, 0.25);
  border-radius: 8px;
}

.ts07-content {
  position: relative;
}

.ts07-rail {
  position: absolute;
  left: 8px;
  top: 0;
  width: 3px;
  height: 100%;
  background: #17141a;
  border-radius: 4px;
  transform-origin: top;
  transform: scaleY(0);
}

@supports (animation-timeline: scroll()) {
  .ts07-rail:not(.is-demo) {
    animation: ts07-draw linear both;
    animation-timeline: scroll(nearest block);
  }
}
@supports not (animation-timeline: scroll()) {
  .ts07-rail:not(.is-demo) {
    transform: scaleY(1);
  }
}
@keyframes ts07-draw {
  from {
    transform: scaleY(0);
  }
  to {
    transform: scaleY(1);
  }
}
.ts07-item {
  padding: 8px 0;
  color: #17141a;
  font: 600 13px/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  border-bottom: 1px solid rgba(23, 20, 26, 0.14);
}

.ts07-rail.is-demo {
  animation: ts07-draw-loop 2s linear infinite;
}

@keyframes ts07-draw-loop {
  0% {
    transform: scaleY(0);
  }
  100% {
    transform: scaleY(1);
  }
}
@media (prefers-reduced-motion: reduce) {
  .ts07-rail, .ts07-rail.is-demo {
    animation: none !important;
    transform: scaleY(1) !important;
  }
}

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

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

export interface ScrollProgressLineProps {
  color?: string;
  times?: string[];
}

// animation-timeline: scroll() 는 브라우저 지원이 갈린다 — Firefox·Safari 는 아직 없다.
// 지원 브라우저에서는 이 상자를 안에서 스크롤하면 JS 없이 옆 선이 진행률만큼 그려진다.
export default function ScrollProgressLine({
  color = "#17141a",
  times = ["09:00", "09:20", "10:00", "10:40", "11:10"],
}: ScrollProgressLineProps) {
  const style: Vars = { "--color": color };
  return (
    <div className={styles.box} style={style}>
      <span className={styles.rail} />
      <div className={styles.content}>
        {times.map((t) => (
          <div key={t} className={styles.item}>{t}</div>
        ))}
      </div>
    </div>
  );
}