Shared Axis Y

<!--
  Shared Axis Y - remocn typography primitive for HyperFrames.

  Paste the markup, CSS and script into a composition. Drive the timeline
  integration from a paused GSAP timeline so renders remain deterministic.

  Variables. The script reads each one, falls back to the declared default on
  anything missing or unrecognised, and writes the result as a custom property
  the CSS above consumes. The timeline recipe below is untouched by them: it
  keeps driving one vertical offset, and these decide what that offset means
  on screen. At rest the offset is 0, so every setting lands on the same
  final frame.

    - direction (up | down, default up): which side of the baseline the words
      travel in from. up rises into place, down drops in.
    - distance (close | standard | far, default standard): scales the offset.
      close covers half the run, far nearly double, in the same time.
    - tone (ink | paper | accent, default ink): word colour. 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: words rise 32px
  into place in near-black.
-->

<div
  class="hf-remocn-shared-axis-y"
  data-composition-variables='[
    { "id": "direction", "type": "enum", "role": "motion", "label": "Direction", "description": "Which side of the baseline the words travel in from.", "default": "up", "options": [{ "value": "up", "label": "Up" }, { "value": "down", "label": "Down" }] },
    { "id": "distance", "type": "enum", "role": "motion", "label": "Distance", "description": "Scales the vertical offset, so the words 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": "Word 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>Plan</span><span>Debug</span><span>Ask</span>
</div>

<style>
  .hf-remocn-shared-axis-y {
    color: var(--hf-word-color, #18181b);
    font-family: Inter, system-ui, sans-serif;
    font-weight: 900;
    letter-spacing: -0.04em;
  }
  .hf-remocn-shared-axis-y {
    display: inline-flex;
    gap: 12px;
    font-size: 56px;
    line-height: 1;
  }
  .hf-remocn-shared-axis-y span {
    display: inline-block;
    transform: translate(
        var(--hf-word-x, 0px),
        calc(var(--hf-word-y, 0px) * var(--hf-word-axis-y, 1))
      )
      scale(var(--hf-word-scale, 1));
    filter: blur(var(--hf-word-blur, 0px));
    will-change: transform, filter, opacity;
  }
</style>

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

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

    // Unrecognised overrides return to their declared defaults.
    var signs = { up: 1, down: -1 };
    var reaches = { close: 0.5, standard: 1, far: 1.85 };
    var tones = {
      ink: "#18181b",
      paper: "#fafafa",
      accent: "var(--brand, #34d399)",
    };

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

    var sign = signs[pick(signs, vars.direction, "up")];
    var reach = reaches[pick(reaches, vars.distance, "standard")];
    var tone = tones[pick(tones, vars.tone, "ink")];

    var roots = document.querySelectorAll(".hf-remocn-shared-axis-y");
    for (var i = 0; i < roots.length; i += 1) {
      roots[i].style.setProperty("--hf-word-axis-y", String(sign * reach));
      roots[i].style.setProperty("--hf-word-color", tone);
    }
  })();
</script>

<!--
  Timeline integration:
  tl.fromTo('.hf-remocn-shared-axis-y span', { opacity: 0, '--hf-word-y': '32px' }, { opacity: 1, '--hf-word-y': '0px', duration: 0.22, stagger: 0.075, ease: 'power2.out' }, startTime);
-->