02Twinkling stars

<main class="stage">
  <div class="field" aria-hidden="true">
    <span class="p" style="--i:0"></span>
    <span class="p" style="--i:1"></span>
    <span class="p" style="--i:2"></span>
    <span class="p" style="--i:3"></span>
    <span class="p" style="--i:4"></span>
    <span class="p" style="--i:5"></span>
    <span class="p" style="--i:6"></span>
    <span class="p" style="--i:7"></span>
    <span class="p" style="--i:8"></span>
    <span class="p" style="--i:9"></span>
    <span class="p" style="--i:10"></span>
    <span class="p" style="--i:11"></span>
    <span class="p" style="--i:12"></span>
    <span class="p" style="--i:13"></span>
    <span class="p" style="--i:14"></span>
    <span class="p" style="--i:15"></span>
    <span class="p" style="--i:16"></span>
    <span class="p" style="--i:17"></span>
    <span class="p" style="--i:18"></span>
    <span class="p" style="--i:19"></span>
    <span class="p" style="--i:20"></span>
    <span class="p" style="--i:21"></span>
    <span class="p" style="--i:22"></span>
    <span class="p" style="--i:23"></span>
  </div>
  <p class="caption">Tonight Only</p>
</main>

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

// ── 변수 3개 ──────────────────────────────
$duration: $dur-base * 6;   // 1.8s 기준 — 항목마다 다르게 늘려 불규칙해 보이게 한다
$easing: ease-in-out;
$color: $subject-ink;

// ── 데모 무대 ───────────────────────────────
@include stage($stage-yellow);

.field { position: absolute; inset: 0; overflow: hidden; pointer-events: none; }

.caption {
  position: relative; z-index: 1; margin: 0;
  color: $subject-ink; font-weight: 700; font-size: clamp(16px, 5vw, 22px); line-height: 1; font-family: inherit;
}

.p {
  position: absolute;
  width: 5px; height: 5px;
  border-radius: 50%;
  background: $color;
  box-shadow: 0 0 10px rgba($color, .55);
  opacity: .2;
  animation: twinkle $duration $easing infinite;
  animation-delay: calc(var(--i) * -0.31s);
}

@for $i from 1 through 24 {
  .p:nth-child(#{$i}) {
    left: ((($i * 41) % 93)) * 1%;
    top: ((($i * 67) % 80)) * 1%;
    animation-duration: $duration + ($i % 5) * .35s;
  }
}

@keyframes twinkle {
  0%, 100% { transform: scale(.7); opacity: .2; }
  50%       { transform: scale(1.3); opacity: 1; }
}

// ── 접근성: 반짝임을 끄고 희미한 별만 남긴다 ────────────
@media (prefers-reduced-motion: reduce) {
  .p { animation: none; opacity: .55; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.field {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
}

.caption {
  position: relative;
  z-index: 1;
  margin: 0;
  color: #17141a;
  font-weight: 700;
  font-size: clamp(16px, 5vw, 22px);
  line-height: 1;
  font-family: inherit;
}

.p {
  position: absolute;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: #17141a;
  box-shadow: 0 0 10px rgba(23, 20, 26, 0.55);
  opacity: 0.2;
  animation: twinkle 1800ms ease-in-out infinite;
  animation-delay: calc(var(--i) * -0.31s);
}

.p:nth-child(1) {
  left: 41%;
  top: 67%;
  animation-duration: 2150ms;
}

.p:nth-child(2) {
  left: 82%;
  top: 54%;
  animation-duration: 2500ms;
}

.p:nth-child(3) {
  left: 30%;
  top: 41%;
  animation-duration: 2850ms;
}

.p:nth-child(4) {
  left: 71%;
  top: 28%;
  animation-duration: 3200ms;
}

.p:nth-child(5) {
  left: 19%;
  top: 15%;
  animation-duration: 1800ms;
}

.p:nth-child(6) {
  left: 60%;
  top: 2%;
  animation-duration: 2150ms;
}

.p:nth-child(7) {
  left: 8%;
  top: 69%;
  animation-duration: 2500ms;
}

.p:nth-child(8) {
  left: 49%;
  top: 56%;
  animation-duration: 2850ms;
}

.p:nth-child(9) {
  left: 90%;
  top: 43%;
  animation-duration: 3200ms;
}

.p:nth-child(10) {
  left: 38%;
  top: 30%;
  animation-duration: 1800ms;
}

.p:nth-child(11) {
  left: 79%;
  top: 17%;
  animation-duration: 2150ms;
}

.p:nth-child(12) {
  left: 27%;
  top: 4%;
  animation-duration: 2500ms;
}

.p:nth-child(13) {
  left: 68%;
  top: 71%;
  animation-duration: 2850ms;
}

.p:nth-child(14) {
  left: 16%;
  top: 58%;
  animation-duration: 3200ms;
}

.p:nth-child(15) {
  left: 57%;
  top: 45%;
  animation-duration: 1800ms;
}

.p:nth-child(16) {
  left: 5%;
  top: 32%;
  animation-duration: 2150ms;
}

.p:nth-child(17) {
  left: 46%;
  top: 19%;
  animation-duration: 2500ms;
}

.p:nth-child(18) {
  left: 87%;
  top: 6%;
  animation-duration: 2850ms;
}

.p:nth-child(19) {
  left: 35%;
  top: 73%;
  animation-duration: 3200ms;
}

.p:nth-child(20) {
  left: 76%;
  top: 60%;
  animation-duration: 1800ms;
}

.p:nth-child(21) {
  left: 24%;
  top: 47%;
  animation-duration: 2150ms;
}

.p:nth-child(22) {
  left: 65%;
  top: 34%;
  animation-duration: 2500ms;
}

.p:nth-child(23) {
  left: 13%;
  top: 21%;
  animation-duration: 2850ms;
}

.p:nth-child(24) {
  left: 54%;
  top: 8%;
  animation-duration: 3200ms;
}

@keyframes twinkle {
  0%, 100% {
    transform: scale(0.7);
    opacity: 0.2;
  }
  50% {
    transform: scale(1.3);
    opacity: 1;
  }
}
@media (prefers-reduced-motion: reduce) {
  .p {
    animation: none;
    opacity: 0.55;
  }
}

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

export type StarsTwinkleProps = {
  /** 애니메이션 기준 시간(ms) */
  duration?: number;
  /** CSS easing */
  easing?: string;
  /** 피사체 색 */
  color?: string;
};

type Vars = CSSProperties & { "--i"?: number };

const COUNT = 24;

export default function StarsTwinkle({
  duration = 1800,
  easing = "ease-in-out",
  color = "#17141a",
}: StarsTwinkleProps) {
  const vars = {
    "--duration": `${duration}ms`,
    "--easing": easing,
    "--color": color,
  } as CSSProperties;

  return (
    <div className={styles.field} style={vars} aria-hidden="true">
      {Array.from({ length: COUNT }, (_, i) => (
        <span key={i} className={styles.p} style={{ "--i": i } as Vars} />
      ))}
    </div>
  );
}