Number Wheel

<!--
  Number Wheel - rolling digit counter.

  Markup:
    <span class="hf-number-wheel" data-value="30222"></span>

  Paste this snippet once. It builds one column per digit. Animate the generated
  .hf-number-wheel-strip elements with the data-target-y custom property.

  Variables. The script reads each one, falls back to the declared default on
  anything missing or unrecognised, and either builds a longer strip or writes a
  custom property the CSS above consumes. Every strip still starts on 0 and
  still lands on its own digit, so only the run in between changes.

    - spin (single | double | triple, default single): how many full 0 to 9
      revolutions each column adds before it lands. Extra revolutions lengthen
      the strip and push --hf-number-target-y further, so the reel covers more
      ground in the same time. Nothing moves at rest, so this one only shows
      once the timeline runs.
    - spacing (tight | standard | wide, default standard): the gap between digit
      columns.
    - tone (inherit | ink | paper | accent, default inherit): digit colour.
      inherit leaves the surrounding text colour alone, ink is near-black for
      light frames, paper near-white for dark ones, accent rides --brand.

  On every default the result is identical to the original: one column per
  digit, each rolling 0 up to its own digit in the inherited text colour.
-->

<style
  data-composition-variables='[
    { "id": "spin", "type": "enum", "role": "motion", "label": "Spin", "description": "How many full 0 to 9 revolutions each column adds before it lands, which is how far the reel travels in the same time.", "default": "single", "options": [{ "value": "single", "label": "Single" }, { "value": "double", "label": "Double" }, { "value": "triple", "label": "Triple" }] },
    { "id": "spacing", "type": "enum", "role": "layout", "label": "Spacing", "description": "Gap between the digit columns.", "default": "standard", "options": [{ "value": "tight", "label": "Tight" }, { "value": "standard", "label": "Standard" }, { "value": "wide", "label": "Wide" }] },
    { "id": "tone", "type": "enum", "role": "style", "label": "Tone", "description": "Digit colour: inherit keeps the surrounding text colour, ink suits light frames, paper suits dark ones, accent rides --brand.", "default": "inherit", "options": [{ "value": "inherit", "label": "Inherit" }, { "value": "ink", "label": "Ink" }, { "value": "paper", "label": "Paper" }, { "value": "accent", "label": "Accent" }] }
  ]'
>
  .hf-number-wheel {
    display: inline-flex;
    align-items: baseline;
    gap: var(--hf-wheel-gap, 0.02em);
    color: var(--hf-wheel-color, inherit);
    font-variant-numeric: tabular-nums;
  }
  .hf-number-wheel-digit {
    display: inline-block;
    height: 1em;
    overflow: hidden;
  }
  .hf-number-wheel-strip {
    display: grid;
    transform: translateY(0em);
    will-change: transform;
  }
  .hf-number-wheel-strip span {
    height: 1em;
    line-height: 1em;
  }
</style>

<script>
  (function () {
    const vars =
      window.__hyperframes && window.__hyperframes.getVariables
        ? window.__hyperframes.getVariables()
        : {};

    // Unrecognised overrides return to their declared defaults.
    const spins = { single: 0, double: 1, triple: 2 };
    const gaps = { tight: "0em", standard: "0.02em", wide: "0.14em" };
    const tones = {
      inherit: "inherit",
      ink: "#18181b",
      paper: "#fafafa",
      accent: "var(--brand, #34d399)",
    };
    const pick = (table, value, fallback) =>
      Object.prototype.hasOwnProperty.call(table, value) ? table[value] : table[fallback];

    const cycles = pick(spins, vars.spin, "single");
    const gap = pick(gaps, vars.spacing, "standard");
    const tone = pick(tones, vars.tone, "inherit");

    document.querySelectorAll(".hf-number-wheel").forEach((el) => {
      if (el.dataset.hfNumberWheelReady === "1") return;
      el.style.setProperty("--hf-wheel-gap", gap);
      el.style.setProperty("--hf-wheel-color", tone);
      const value = el.dataset.value || "0";
      el.textContent = "";
      for (const char of value) {
        if (!/\d/.test(char)) {
          el.append(document.createTextNode(char));
          continue;
        }
        const stops = cycles * 10 + Number(char);
        const frame = document.createElement("span");
        frame.className = "hf-number-wheel-digit";
        const strip = document.createElement("span");
        strip.className = "hf-number-wheel-strip";
        strip.style.setProperty("--hf-number-target-y", `${-stops}em`);
        for (let i = 0; i <= stops; i++) {
          const step = document.createElement("span");
          step.textContent = String(i % 10);
          strip.appendChild(step);
        }
        frame.appendChild(strip);
        el.appendChild(frame);
      }
      el.dataset.hfNumberWheelReady = "1";
    });
  })();
</script>

<!--
  Timeline integration:

  tl.to(".hf-number-wheel-strip", {
    y: (_, strip) => strip.style.getPropertyValue("--hf-number-target-y"),
    duration: 1.1,
    ease: "power3.out",
    stagger: 0.05,
  }, startTime);
-->