05Horizontal timeline parallax

<main class="stage is-demo">
  <div class="hline">
    <span class="hline__label">Timeline</span>
    <div class="hline__track">
      <span class="hline__card">01</span>
      <span class="hline__card">02</span>
      <span class="hline__card">03</span>
      <span class="hline__card">04</span>
    </div>
  </div>
</main>

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

// ── 변수 3개. 변형은 이것만 바꾼다 ──────────────────────────
$travel: 120px;                                  // 가로 이동 거리
$gap: 14px;                                       // 카드 사이 간격
$color: $subject-cream;                          // 카드 색 (ink 무대라 cream)

@include stage($stage-ink);

.hline {
  position: relative;
  width: 100%;
  height: 100%;
  overflow: hidden;
  display: grid;
  align-content: center;
  gap: 18px;
}
.hline__label {
  padding-left: 16px;
  color: rgba($color, .7);
  font: 700 clamp(12px, 3.6vw, 14px)/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  letter-spacing: .04em;
}
.hline__track {
  display: flex;
  gap: $gap;
  padding-left: 16px;

  // ── 실제 사용 코드: 세로 스크롤을 그대로 가로 이동으로 쓴다 ──
  @supports (animation-timeline: scroll()) {
    animation: travel linear both;
    animation-timeline: scroll(root);
  }
  @supports not (animation-timeline: scroll()) { transform: none; }
}
.hline__card {
  flex: none;
  width: 64px;
  height: 64px;
  border-radius: $r-card;
  background: $color;
  color: $stage-ink;
  display: grid;
  place-items: center;
  font: 700 18px/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
}

@keyframes travel { from { transform: translateX(0); } to { transform: translateX(-#{$travel}); } }

// ── 데모(.is-demo): 왕복 루프로 흉내 ────────
.stage.is-demo .hline__track { animation: travel-loop $dur-loop ease-in-out infinite; }
@keyframes travel-loop { 0%, 100% { transform: translateX(0); } 50% { transform: translateX(-$travel); } }

@media (prefers-reduced-motion: reduce) {
  .hline__track, .stage.is-demo .hline__track { animation: none !important; 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);
}

.hline {
  position: relative;
  width: 100%;
  height: 100%;
  overflow: hidden;
  display: grid;
  align-content: center;
  gap: 18px;
}

.hline__label {
  padding-left: 16px;
  color: rgba(255, 247, 230, 0.7);
  font: 700 clamp(12px, 3.6vw, 14px)/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  letter-spacing: 0.04em;
}

.hline__track {
  display: flex;
  gap: 14px;
  padding-left: 16px;
}
@supports (animation-timeline: scroll()) {
  .hline__track {
    animation: travel linear both;
    animation-timeline: scroll(root);
  }
}
@supports not (animation-timeline: scroll()) {
  .hline__track {
    transform: none;
  }
}

.hline__card {
  flex: none;
  width: 64px;
  height: 64px;
  border-radius: 16px;
  background: #fff7e6;
  color: #17141a;
  display: grid;
  place-items: center;
  font: 700 18px/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
}

@keyframes travel {
  from {
    transform: translateX(0);
  }
  to {
    transform: translateX(-120px);
  }
}
.stage.is-demo .hline__track {
  animation: travel-loop 2s ease-in-out infinite;
}

@keyframes travel-loop {
  0%, 100% {
    transform: translateX(0);
  }
  50% {
    transform: translateX(-120px);
  }
}
@media (prefers-reduced-motion: reduce) {
  .hline__track, .stage.is-demo .hline__track {
    animation: none !important;
    transform: none;
  }
}

import type { CSSProperties, ReactNode } from "react";
import styles from "./HorizontalTimeline.module.scss";

export type HorizontalTimelineProps = {
  /** 카드 내용 (숫자·짧은 라벨) */
  items: ReactNode[];
  label?: string;
  /** 가로 이동 거리 (기본 120px) */
  travel?: number;
  /** 카드 사이 간격 (기본 14px) */
  gap?: number;
  className?: string;
};

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

export default function HorizontalTimeline({
  items,
  label = "Timeline",
  travel = 120,
  gap = 14,
  className = "",
}: HorizontalTimelineProps) {
  const vars: Vars = { "--travel": `${travel}px`, "--gap": `${gap}px` };

  return (
    <div className={`${styles.hline} ${className}`} style={vars}>
      <span className={styles.label}>{label}</span>
      <div className={styles.track}>
        {items.map((item, i) => (
          <span key={i} className={styles.card}>
            {item}
          </span>
        ))}
      </div>
    </div>
  );
}