Number Pop In

<!--
  Number Pop In - 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 either rebuilds the characters or writes
  a custom property the CSS above consumes. The timeline recipe stays untouched:
  it keeps driving one offset, one scale and one blur, and these decide what the
  number is, what colour it is, and how far that offset carries it.

    - value (any text, default 5.7): the number itself. Every character becomes
      its own span, so the stagger still lands character by character.
    - unit (any text, default k): the small suffix printed after the number.
      Pass an empty string to drop it.
    - lift (close | standard | far, default standard): scales the offset the
      timeline drives, so the characters cover a shorter or longer run in the
      same time. The offset is zero at rest, so this one only shows in motion.
    - tone (ink | paper | accent, default ink): number colour. ink is near-black
      for light frames, paper near-white for dark ones, accent rides --brand.
      The suffix follows in the same family.

  On every default the result is identical to the original: 5.7k rising 24px
  through an 8px blur in near-black.
-->

<div
  class="hf-transition-number-pop-in"
  data-composition-variables='[
    { "id": "value", "type": "string", "role": "content", "label": "Value", "description": "The number itself. Every character becomes its own span, so the stagger still lands character by character.", "default": "5.7" },
    { "id": "unit", "type": "string", "role": "content", "label": "Unit", "description": "Small suffix printed after the number. Pass an empty string to drop it.", "default": "k" },
    { "id": "lift", "type": "enum", "role": "motion", "label": "Lift", "description": "Scales the offset the timeline drives, so the characters cover a shorter or longer run in the same time.", "default": "standard", "options": [{ "value": "close", "label": "Close" }, { "value": "standard", "label": "Standard" }, { "value": "far", "label": "Far" }] },
    { "id": "tone", "type": "enum", "role": "style", "label": "Tone", "description": "Number colour: ink for light frames, paper for dark ones, accent rides --brand.", "default": "ink", "options": [{ "value": "ink", "label": "Ink" }, { "value": "paper", "label": "Paper" }, { "value": "accent", "label": "Accent" }] }
  ]'
>
  <span>5</span><span>.</span><span>7</span><small>k</small>
</div>

<style>
  .hf-transition-number-pop-in {
    display: inline-flex;
    align-items: baseline;
    gap: 2px;
    color: var(--hf-number-color, #18181b);
    font-family: Inter, system-ui, sans-serif;
    font-weight: 900;
    letter-spacing: -0.04em;
  }
  .hf-transition-number-pop-in span {
    font-size: 76px;
    line-height: 0.9;
    filter: blur(var(--hf-number-blur, 0px));
    transform: translateY(calc(var(--hf-number-y, 0px) * var(--hf-number-lift, 1)))
      scale(var(--hf-number-scale, 1));
    will-change: transform, filter, opacity;
  }
  .hf-transition-number-pop-in small {
    margin-left: 2px;
    color: var(--hf-number-unit-color, #71717a);
    font-size: 34px;
    font-weight: 850;
  }
</style>

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

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

    // Unrecognised overrides return to their declared defaults.
    var lifts = { close: 0.5, standard: 1, far: 1.75 };
    var tones = {
      ink: { number: "#18181b", unit: "#71717a" },
      paper: { number: "#fafafa", unit: "#a1a1aa" },
      accent: { number: "var(--brand, #34d399)", unit: "var(--brand, #34d399)" },
    };

    function text(value, fallback) {
      return typeof value === "string" ? value : fallback;
    }

    var value = text(vars.value, "5.7");
    if (value === "") value = "5.7";
    var unit = text(vars.unit, "k");
    var lift = Object.prototype.hasOwnProperty.call(lifts, vars.lift) ? vars.lift : "standard";
    var tone = Object.prototype.hasOwnProperty.call(tones, vars.tone) ? vars.tone : "ink";

    var roots = document.querySelectorAll(".hf-transition-number-pop-in");
    for (var i = 0; i < roots.length; i += 1) {
      var root = roots[i];
      root.style.setProperty("--hf-number-lift", String(lifts[lift]));
      root.style.setProperty("--hf-number-color", tones[tone].number);
      root.style.setProperty("--hf-number-unit-color", tones[tone].unit);

      var next = [];
      for (var c = 0; c < value.length; c += 1) {
        var span = document.createElement("span");
        span.textContent = value.charAt(c);
        next.push(span);
      }
      if (unit !== "") {
        var small = document.createElement("small");
        small.textContent = unit;
        next.push(small);
      }
      root.replaceChildren.apply(root, next);
    }
  })();
</script>

<!--
  Timeline integration:
  tl.fromTo('.hf-transition-number-pop-in span, .hf-transition-number-pop-in small', { opacity: 0, '--hf-number-y': '24px', '--hf-number-scale': 0.82, '--hf-number-blur': '8px' }, { opacity: 1, '--hf-number-y': '0px', '--hf-number-scale': 1, '--hf-number-blur': '0px', duration: 0.34, stagger: 0.055, ease: 'back.out(1.8)' }, startTime);
-->