04サムネイルマーカー

<main class="stage">
  <div class="tm is-demo">
    <div class="tm__viewport">
      <div class="tm__track">
        <div class="tm__slide tm__slide--1" style="--thumb:#93a4ca"><span class="tm__cap">ブルー</span></div>
        <div class="tm__slide tm__slide--2" style="--thumb:#c89a8f"><span class="tm__cap">オレンジ</span></div>
        <div class="tm__slide tm__slide--3" style="--thumb:#17141a"><span class="tm__cap">ブラック</span></div>
        <div class="tm__slide tm__slide--1 tm__slide--clone" style="--thumb:#93a4ca" aria-hidden="true"><span class="tm__cap">ブルー</span></div>
      </div>
    </div>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-base;
$easing: $ease-spring;
$color: $subject-cream;               // 활성 썸네일 테두리 색

@include stage($stage-paper);

.tm { width: min(340px, 82vw); overflow: hidden; }

// ── 실제 동작: ::scroll-marker 가 각 슬라이드의 --thumb 색을 물려받아 정사각 썸네일을 만든다 (0줄 JS) ──
.tm__viewport {
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  border-radius: $r-card;
  scrollbar-width: none;
  &::-webkit-scrollbar { display: none; }
}
.tm__viewport::scroll-marker-group {
  display: flex;
  justify-content: center;
  gap: $sp-2;
  margin-top: $sp-3;
}
// ── 무한 루프 이음새: 1번을 트랙 끝에 복제(aria-hidden). 썸네일 마커는 복제분만 숨긴다 ──
.tm__track {
  display: flex;
  width: 400%;
}
.tm__slide {
  flex: 0 0 25%;
  scroll-snap-align: start;
  aspect-ratio: 16 / 10;
  margin-right: $sp-3;
  border-radius: $r-card;
  position: relative;
  overflow: hidden;
  display: grid;
  place-items: end start;
  box-sizing: border-box;
  background: linear-gradient(135deg, var(--thumb), color-mix(in srgb, var(--thumb) 55%, white));

  &::scroll-marker {
    content: "";
    width: $sp-4; height: $sp-4;
    border-radius: $r-xs;
    background: var(--thumb);
    border: 2px solid transparent;
    box-sizing: border-box;
    transition: border-color $duration $easing, transform $duration $easing;
  }
  &::scroll-marker:target-current {
    border-color: $color;
    transform: scale(1.12);
  }
}
.tm__slide--clone::scroll-marker { display: none; }
.tm__slide:last-child { margin-right: 0; }
.tm__slide::before {
  content: ""; position: absolute; top: $sp-4; right: $sp-4;
  width: $sp-8; height: $sp-8; border-radius: 50%;
  background: rgba(255, 255, 255, .78);
}
.tm__slide::after {
  content: ""; position: absolute; left: -8%; right: -8%; bottom: -6%; height: 48%;
  background: rgba(23, 20, 26, .22);
  clip-path: polygon(0% 100%, 20% 40%, 40% 66%, 58% 26%, 76% 60%, 100% 34%, 100% 100%);
}
.tm__cap {
  position: relative; z-index: 1;
  margin: $sp-3;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(23, 20, 26, .38);
  color: $subject-cream;
  font-weight: 600;
  font-size: clamp(12px, 3.2vw, 13px);
  line-height: 1;
  font-family: inherit;
}

// ── 데모 루프: 트랙에 별도 transform 을 얹어 자동으로 넘어간다 (진짜 스크롤·썸네일 클릭은 그대로) ──
// 마지막 칸은 1번의 복제본 — 그곳까지 정상 속도로 가고 100%→0% 점프는 복제본=1번이라 안 보인다 (텔레포트 금지)
.tm.is-demo .tm__track { animation: tm-loop $dur-loop $easing infinite; }
@keyframes tm-loop {
  0%, 8%    { transform: translateX(0%); }
  31%, 39%  { transform: translateX(calc(-25% - #{$sp-3})); }
  62%, 70%  { transform: translateX(calc(-50% - #{$sp-3 * 2})); }
  92%, 100% { transform: translateX(calc(-75% - #{$sp-3 * 3})); }
}

// ── 접근성 ──────────────────────────────────────────
@media (prefers-reduced-motion: reduce) {
  .tm.is-demo .tm__track { animation: none !important; }
  .tm__slide::scroll-marker { transition: none; }
}

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);
}

.tm {
  width: min(340px, 82vw);
  overflow: hidden;
}

.tm__viewport {
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  border-radius: 16px;
  scrollbar-width: none;
}
.tm__viewport::-webkit-scrollbar {
  display: none;
}

.tm__viewport::scroll-marker-group {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 12px;
}

.tm__track {
  display: flex;
  width: 400%;
}

.tm__slide {
  flex: 0 0 25%;
  scroll-snap-align: start;
  aspect-ratio: 16/10;
  margin-right: 12px;
  border-radius: 16px;
  position: relative;
  overflow: hidden;
  display: grid;
  place-items: end start;
  box-sizing: border-box;
  background: linear-gradient(135deg, var(--thumb), color-mix(in srgb, var(--thumb) 55%, white));
}
.tm__slide::scroll-marker {
  content: "";
  width: 16px;
  height: 16px;
  border-radius: 4px;
  background: var(--thumb);
  border: 2px solid transparent;
  box-sizing: border-box;
  transition: border-color 300ms cubic-bezier(0.2, 0.8, 0.2, 1), transform 300ms cubic-bezier(0.2, 0.8, 0.2, 1);
}
.tm__slide::scroll-marker:target-current {
  border-color: #fff7e6;
  transform: scale(1.12);
}

.tm__slide--clone::scroll-marker {
  display: none;
}

.tm__slide:last-child {
  margin-right: 0;
}

.tm__slide::before {
  content: "";
  position: absolute;
  top: 16px;
  right: 16px;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.78);
}

.tm__slide::after {
  content: "";
  position: absolute;
  left: -8%;
  right: -8%;
  bottom: -6%;
  height: 48%;
  background: rgba(23, 20, 26, 0.22);
  clip-path: polygon(0% 100%, 20% 40%, 40% 66%, 58% 26%, 76% 60%, 100% 34%, 100% 100%);
}

.tm__cap {
  position: relative;
  z-index: 1;
  margin: 12px;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.38);
  color: #fff7e6;
  font-weight: 600;
  font-size: clamp(12px, 3.2vw, 13px);
  line-height: 1;
  font-family: inherit;
}

.tm.is-demo .tm__track {
  animation: tm-loop 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@keyframes tm-loop {
  0%, 8% {
    transform: translateX(0%);
  }
  31%, 39% {
    transform: translateX(calc(-25% - 12px));
  }
  62%, 70% {
    transform: translateX(calc(-50% - 24px));
  }
  92%, 100% {
    transform: translateX(calc(-75% - 36px));
  }
}
@media (prefers-reduced-motion: reduce) {
  .tm.is-demo .tm__track {
    animation: none !important;
  }
  .tm__slide::scroll-marker {
    transition: none;
  }
}

// 썸네일도 브라우저가 ::scroll-marker 로 자동 생성한다(0줄). 색은 슬라이드의 --thumb 변수를 물려받는다.
// 이 3줄은 미리보기 자동 재생만 멈춘다.
document.querySelector('.tm__viewport').addEventListener('pointerdown', function () {
  document.querySelector('.tm').classList.remove('is-demo');
});

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

const SLIDES: { label: string; thumb: string }[] = [
  { label: "블루", thumb: "#2f6df6" },
  { label: "오렌지", thumb: "#ff4d1f" },
  { label: "블랙", thumb: "#17141a" },
];

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

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

export default function ThumbnailsMarkers({ duration = 300, easing = "cubic-bezier(.2,.8,.2,1)", color = "#fff7e6" }: ThumbnailsMarkersProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  return (
    <div className={styles.tm} style={vars}>
      {/* 썸네일도 ::scroll-marker 하나 — 색은 슬라이드의 --thumb 변수를 물려받는다 */}
      <div className={styles.viewport}>
        <div className={styles.track}>
          {SLIDES.map((s) => (
            <div key={s.label} className={styles.slide} style={{ "--thumb": s.thumb } as Vars}>
              <span className={styles.cap}>{s.label}</span>
            </div>
          ))}
        </div>
      </div>
    </div>
  );
}