Text Stagger

<!--
  Text Stagger - transitions.dev-inspired primitive for HyperFrames.

  Paste the markup, CSS and script into a composition. Use the timeline
  integration note at the bottom as the starting point for deterministic GSAP
  animation.

  Variables. The script reads each one, falls back to the declared default on
  anything missing or unrecognised, and writes the result into the markup or
  into a custom property the CSS above consumes. The timeline recipe below is
  untouched by them: it keeps driving the same rise, blur and shimmer sweep.

    - text (string, default "Build motion systems fast"): the headline. It is
      split on whitespace and every word becomes its own span, so the word
      count decides how many steps the stagger has. Blank falls back to the
      default sentence.
    - size (number, default 74, clamped to 24-160 px): type size of every
      word. Line height stays proportional, so the block grows and shrinks as
      one. A missing or non-numeric value falls back to 74.
    - tone (ink | paper, default ink): base word colour. ink is near-black for
      light frames, paper near-white for dark ones. It paints both the resting
      words and the two dark stops of the shimmer gradient.
    - accent (blue | green | violet, default blue): the shimmer colour that the
      second timeline step sweeps across the words. It sits outside the visible
      band while the words rest, so it only shows once that sweep runs.

  On every default the result is identical to the original: four near-black
  74px words that rise through a blur and take one sky-blue shimmer pass.
-->

<div
  class="hf-transition-text-stagger"
  data-composition-variables='[
    {"id": "text", "type": "string", "role": "content", "label": "Text", "description": "Headline copy. Every whitespace-separated word becomes one staggered span.", "default": "Build motion systems fast"},
    {"id": "size", "type": "number", "role": "layout", "label": "Size", "description": "Type size of every word in pixels, clamped to 24-160. Line height stays proportional.", "default": 74, "min": 24, "max": 160, "step": 1, "unit": "px"},
    {"id": "tone", "type": "enum", "role": "style", "label": "Tone", "description": "Base word colour: ink for light frames, paper for dark ones.", "default": "ink", "options": [{"value": "ink", "label": "Ink"}, {"value": "paper", "label": "Paper"}]},
    {"id": "accent", "type": "enum", "role": "style", "label": "Accent", "description": "Colour of the shimmer the second timeline step sweeps across the words.", "default": "blue", "options": [{"value": "blue", "label": "Blue"}, {"value": "green", "label": "Green"}, {"value": "violet", "label": "Violet"}]}
  ]'
>
  <span>Build</span>
  <span>motion</span>
  <span>systems</span>
  <span>fast</span>
</div>

<style>
  .hf-transition-text-stagger {
    display: flex;
    flex-wrap: wrap;
    gap: 0.24em;
    color: var(--hf-stagger-ink, #111827);
    font:
      900 74px/0.95 Inter,
      system-ui,
      sans-serif;
    font-size: var(--hf-stagger-size, 74px);
    letter-spacing: -0.045em;
  }
  .hf-transition-text-stagger span {
    display: inline-block;
    background: linear-gradient(
      90deg,
      var(--hf-stagger-ink, #111827),
      var(--hf-stagger-ink, #111827),
      var(--hf-stagger-accent, #38bdf8),
      var(--hf-stagger-ink, #111827)
    );
    background-size: 240% 100%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    will-change: transform, opacity, filter, background-position;
  }
</style>

<script>
  (function () {
    "use strict";

    var vars =
      window.__hyperframes && window.__hyperframes.getVariables
        ? window.__hyperframes.getVariables()
        : {};

    // Unrecognised overrides return to their declared defaults.
    var DEFAULT_TEXT = "Build motion systems fast";
    var tones = { ink: "#111827", paper: "#f8fafc" };
    var accents = { blue: "#38bdf8", green: "#34d399", violet: "#a78bfa" };

    function pick(table, value, fallback) {
      return Object.prototype.hasOwnProperty.call(table, value) ? value : fallback;
    }

    var words = String(vars.text == null ? DEFAULT_TEXT : vars.text)
      .split(/\s+/)
      .filter(function (word) {
        return word.length > 0;
      });
    if (words.length === 0) words = DEFAULT_TEXT.split(" ");

    // Number(null) is 0, so null has to miss the numeric branch and clamp back
    // to the declared default instead of snapping to the minimum.
    var size = typeof vars.size === "number" ? vars.size : parseFloat(vars.size);
    if (!isFinite(size)) size = 74;
    size = Math.min(160, Math.max(24, size));

    var tone = tones[pick(tones, vars.tone, "ink")];
    var accent = accents[pick(accents, vars.accent, "blue")];

    var roots = document.querySelectorAll(".hf-transition-text-stagger");
    for (var i = 0; i < roots.length; i += 1) {
      var root = roots[i];
      root.style.setProperty("--hf-stagger-size", size + "px");
      root.style.setProperty("--hf-stagger-ink", tone);
      root.style.setProperty("--hf-stagger-accent", accent);
      // Rebuilt without whitespace between the spans: whitespace-only text
      // between flex items is not rendered, so this matches the markup above.
      root.textContent = "";
      for (var w = 0; w < words.length; w += 1) {
        var span = document.createElement("span");
        span.textContent = words[w];
        root.appendChild(span);
      }
    }
  })();
</script>

<!--
  Timeline integration:
  tl.fromTo('.hf-transition-text-stagger span', { opacity: 0, y: 48, filter: 'blur(14px)' }, { opacity: 1, y: 0, filter: 'blur(0px)', duration: 0.54, stagger: 0.09, ease: 'power3.out' }, 0.35);
  tl.to('.hf-transition-text-stagger span', { backgroundPosition: '100% 0%', duration: 0.72, stagger: 0.04, ease: 'power2.inOut' }, 1.05);
-->