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55 Sparkle scatter

Motion · Type in motion
Sparkle scatter

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motion-sparkle-scatter-everything.md

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Prompt

1.2 KB 
Sparkle scatter — Sparkle ornaments around a title

Scatter four-point star ornaments around a heading, one after another. Draw each star as an SVG path (M0 -10 C1 -3 3 -1 10 0 C3 1 1 3 0 10 C-1 3 -3 1 -10 0 C-3 -1 -1 -3 0 -10Z) and place twelve of them outside the heading’s box at 16–40px, alternating accent and ink colours. Star k appears when progress ÷ 0.9 in a 340vh pinned section passes a value from 0.08 up to 0.88, in order, then over the next 0.14 its scale rises from 0 to 1 with easeOutBack (1 + 2.7(t−1)³ + 1.7(t−1)²) and its opacity from 0 to 1. Each star rotates 90° as it appears and keeps turning slowly with the scroll. Never overlap the lettering. Keep the heading as real text and mark the ornaments aria-hidden. With reduced motion show every star already in place. Implement it with CSS and JavaScript only, without any library.

Do not drop:
- Place stars only outside the heading; never overlap the lettering
- Timing, size and rotation depend on progress alone, so scrolling back removes them in order
- Mark ornaments aria-hidden and keep the heading as real text
- With reduced motion show every star in place

A working example (one self-contained HTML file): https://design-vault.pages.dev/designs/motion-sparkle-scatter/demo.html

Files

demo.html

9.8 KB

/designs/motion-sparkle-scatter/demo.html — One self-contained HTML file. CSS and plain JavaScript only; it fetches nothing.

Show contents 
<!doctype html>
<html lang="ja">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>55 装飾を散らす — Sparkle ornaments around a title</title>
<style>
/* dv-motion-base:start */
:root {
  --ground: #FFFFFF;
  --surface: #F3F5F8;
  --ink: #14181F;
  --muted: #5A6472;
  --accent: #1F5FA8;
  --rule: #D8DDE4;
  --accent-soft: color-mix(in srgb, var(--accent) 12%, var(--ground));
  --accent-mid: color-mix(in srgb, var(--accent) 45%, var(--ground));
  --shade: color-mix(in srgb, var(--ink) 14%, transparent);

  --font: "Zen Kaku Gothic New", "Hiragino Sans", "Noto Sans JP", "Yu Gothic", system-ui, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  --t-label: 13px;
  --t-body: 16px;
  --t-lead: 20px;
  --t-h2: 32px;
  --t-h1: clamp(40px, 7vw, 72px);

  --s1: 4px;
  --s2: 8px;
  --s3: 16px;
  --s4: 24px;
  --s5: 40px;
  --s6: 64px;
  --s7: 104px;

  --radius: 12px;
  --ease: cubic-bezier(.2, .7, .2, 1);
  --dur: .7s;
  --measure: 1080px;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--ground);
  color: var(--ink);
  font-family: var(--font);
  font-size: var(--t-body);
  line-height: 1.7;
  font-feature-settings: "palt";
  overflow-x: hidden;
}
h1, h2, h3, p, ul, ol, figure { margin: 0; padding: 0; }
ul, ol { list-style: none; }
.dv-wrap { width: min(100% - 2 * var(--s4), var(--measure)); margin-inline: auto; }
.dv-label {
  min-height: 72vh;
  display: grid;
  align-content: center;
  gap: var(--s3);
  padding-block: var(--s6);
  border-bottom: 1px solid var(--rule);
}
.dv-num { font-family: var(--mono); font-size: var(--t-lead); font-weight: 700; color: var(--accent); letter-spacing: .04em; }
.dv-name { font-size: var(--t-h1); font-weight: 700; line-height: 1.15; letter-spacing: .01em; }
.dv-ai { font-family: var(--mono); font-size: var(--t-lead); color: var(--muted); }
.dv-desc { font-size: var(--t-lead); color: var(--ink); }
.dv-hint { font-size: var(--t-label); color: var(--muted); letter-spacing: .12em; margin-top: var(--s4); }
.dv-stage { padding-block: var(--s7); }
.dv-h2 { font-size: var(--t-h2); font-weight: 700; line-height: 1.3; }
.dv-lead { font-size: var(--t-lead); color: var(--muted); }
.dv-eyebrow { font-family: var(--mono); font-size: var(--t-label); color: var(--accent); letter-spacing: .12em; text-transform: uppercase; }
.dv-card { background: var(--surface); border: 1px solid var(--rule); border-radius: var(--radius); padding: var(--s4); }
.dv-ph {
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--accent-soft), var(--accent-mid) 60%, var(--accent));
  aspect-ratio: 16 / 9;
}
.dv-ph--alt { background: linear-gradient(200deg, var(--surface), var(--accent-soft) 55%, var(--accent-mid)); }
.dv-ph--ink { background: linear-gradient(160deg, var(--ink), color-mix(in srgb, var(--ink) 55%, var(--accent))); }
.dv-end {
  min-height: 60vh;
  display: grid;
  place-items: center;
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-family: var(--mono);
  font-size: var(--t-label);
  letter-spacing: .12em;
}
/* dv-motion-base:end */

/* ---- この演出だけの CSS。色は var(--…) か color-mix() のみ ---- */
.stack { display: grid; gap: var(--s6); }
.sp-zone { height: 340vh; }
.sp-stick { position: sticky; top: 0; height: 100vh; display: grid; place-items: center; overflow: clip; }
.sp-box { position: relative; padding: var(--s6) var(--s5); }
.sp-title { position: relative; font-size: clamp(36px, 9.6vw, 120px); font-weight: 700; line-height: 1.2; text-align: center; }
.sp-star { position: absolute; left: var(--x); top: var(--y); width: var(--w); height: var(--w); margin: calc(var(--w) / -2) 0 0 calc(var(--w) / -2); fill: var(--accent); }
.sp-star--ink { fill: var(--ink); }
.sp-star { transform: scale(var(--s, 0)) rotate(var(--r, 0deg)); opacity: var(--o, 0); }

@media (prefers-reduced-motion: reduce) {
  .sp-zone { height: auto; }
  .sp-stick { position: static; height: auto; padding-block: var(--s6); }
  .sp-star { transform: none; opacity: 1; }
}
</style>
</head>
<body data-motion-number="55">
<header class="dv-label">
  <div class="dv-wrap">
    <p class="dv-num">55</p>
    <h1 class="dv-name">装飾を散らす</h1>
    <p class="dv-ai">Sparkle ornaments around a title</p>
    <p class="dv-desc">見出しのまわりに星が順にまたたく</p>
    <p class="dv-hint">SCROLL ↓</p>
  </div>
</header>

<main class="dv-stage">
<div class="dv-wrap stack">
    <section class="dv-card">
      <p class="dv-eyebrow">Section 1</p>
      <h2 class="dv-h2">見出しが入ります</h2>
      <p class="dv-lead">本文のダミーです。スクロールすると、下の見出しのまわりに星の飾りが順にまたたいて散ります。</p>
    </section>
  </div>

  <section class="sp-zone" data-progress="pin">
    <div class="sp-stick">
      <div class="sp-box">
        <h2 class="sp-title">装飾を散らす</h2>
        <div class="sp-stars" aria-hidden="true"></div>
      </div>
    </div>
  </section>

  <div class="dv-wrap stack">
    <section class="dv-card">
      <p class="dv-eyebrow">Section 2</p>
      <h2 class="dv-h2">見出しが入ります</h2>
      <p class="dv-lead">本文のダミーです。飾りは見出しの外側にだけ置き、文字には重ねません。</p>
    </section>
  </div>
</main>

<footer class="dv-end">END — 55 装飾を散らす</footer>

<script>
/* dv-motion-helpers:start */
const dvReduce = matchMedia('(prefers-reduced-motion: reduce)').matches;
document.documentElement.classList.add('js');

/**
 * 画面に入った要素へ .is-in を付ける。
 * data-reveal="repeat" の要素は画面を出たら外す（何度でも再生）。
 */
function dvReveal(selector = '[data-reveal]', { threshold = 0.2, rootMargin = '0px 0px -8% 0px' } = {}) {
  const els = [...document.querySelectorAll(selector)];
  if (dvReduce || !('IntersectionObserver' in window)) {
    els.forEach((el) => el.classList.add('is-in'));
    return;
  }
  const io = new IntersectionObserver((entries) => {
    for (const e of entries) {
      if (e.isIntersecting) {
        e.target.classList.add('is-in');
        if (e.target.dataset.reveal !== 'repeat') io.unobserve(e.target);
      } else if (e.target.dataset.reveal === 'repeat') {
        e.target.classList.remove('is-in');
      }
    }
  }, { threshold, rootMargin });
  els.forEach((el) => io.observe(el));
}

/**
 * スクロール量を 0〜1 にして、各 [data-progress] 要素の CSS 変数 --p に書く。
 *   data-progress="through" : 要素の上端が画面の下端に来たとき 0、下端が画面の上端を抜けたとき 1
 *   data-progress="pin"     : 要素の上端が画面の上端に来たとき 0、下端が画面の下端に来たとき 1
 *                             （中に position: sticky の箱を持つ、背の高い区画用）
 *   data-progress="page"    : ページ全体のスクロール量
 * onUpdate(el, p) を渡すと、値が変わるたびに呼ばれる。
 */
function dvProgress(onUpdate) {
  const els = [...document.querySelectorAll('[data-progress]')];
  const clamp = (n) => Math.min(1, Math.max(0, n));
  let queued = false;
  const measure = () => {
    queued = false;
    const vh = window.innerHeight;
    for (const el of els) {
      const r = el.getBoundingClientRect();
      let p;
      if (el.dataset.progress === 'pin') p = r.height > vh ? -r.top / (r.height - vh) : 0;
      else if (el.dataset.progress === 'page') {
        const max = document.documentElement.scrollHeight - vh;
        p = max > 0 ? window.scrollY / max : 0;
      } else p = (vh - r.top) / (vh + r.height);
      p = clamp(p);
      el.style.setProperty('--p', p.toFixed(4));
      if (onUpdate) onUpdate(el, p);
    }
  };
  const request = () => {
    if (!queued) { queued = true; requestAnimationFrame(measure); }
  };
  addEventListener('scroll', request, { passive: true });
  addEventListener('resize', request);
  measure();
}
/* dv-motion-helpers:end */

/* ---- この演出だけの JS ---- */
const NS = 'http://www.w3.org/2000/svg';
const host = document.querySelector('.sp-stars');
// 見出しの外側に置く星。x・y は箱の中の割合、w は大きさ、d は現れ始める進み。
const SPEC = [
  { x: '2%', y: '10%', w: '34px', d: 0.08 }, { x: '14%', y: '-4%', w: '18px', d: 0.16, ink: 1 },
  { x: '36%', y: '-8%', w: '26px', d: 0.24 }, { x: '62%', y: '-6%', w: '16px', d: 0.32, ink: 1 },
  { x: '84%', y: '-2%', w: '40px', d: 0.4 }, { x: '98%', y: '22%', w: '20px', d: 0.48 },
  { x: '102%', y: '58%', w: '30px', d: 0.56, ink: 1 }, { x: '90%', y: '104%', w: '22px', d: 0.64 },
  { x: '66%', y: '108%', w: '34px', d: 0.7 }, { x: '40%', y: '106%', w: '16px', d: 0.76, ink: 1 },
  { x: '16%', y: '110%', w: '28px', d: 0.82 }, { x: '-2%', y: '76%', w: '18px', d: 0.88 },
];
const stars = SPEC.map((s) => {
  const svg = document.createElementNS(NS, 'svg');
  svg.setAttribute('viewBox', '-10 -10 20 20');
  svg.setAttribute('class', 'sp-star' + (s.ink ? ' sp-star--ink' : ''));
  svg.style.setProperty('--x', s.x); svg.style.setProperty('--y', s.y); svg.style.setProperty('--w', s.w);
  const path = document.createElementNS(NS, 'path');
  path.setAttribute('d', 'M0 -10 C1 -3 3 -1 10 0 C3 1 1 3 0 10 C-1 3 -3 1 -10 0 C-3 -1 -1 -3 0 -10Z');
  svg.append(path);
  host.append(svg);
  return { el: svg, d: s.d };
});
const easeOutBack = (t) => 1 + 2.7 * Math.pow(t - 1, 3) + 1.7 * Math.pow(t - 1, 2);
function place(p) {
  const q = p / 0.9;
  for (const s of stars) {
    const t = Math.min(1, Math.max(0, (q - s.d) / 0.14));
    s.el.style.setProperty('--s', easeOutBack(t).toFixed(3));
    s.el.style.setProperty('--o', Math.min(1, t * 3).toFixed(3));
    s.el.style.setProperty('--r', (t * 90 + p * 40).toFixed(1) + 'deg');   // 現れるときに回り、そのあともゆっくり回る
  }
}
if (!dvReduce) dvProgress((el, p) => place(p));
</script>
</body>
</html>

/ai/assets/motion-sparkle-scatter.json