Page Slide

<!--
  Page Slide - 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 writes a label or writes a custom
  property the CSS above consumes. The timeline recipe stays untouched: it keeps
  sliding the incoming page over the outgoing one.

    - label_a (any text, default Dashboard): the outgoing page label.
    - label_b (any text, default Analytics): the incoming page label.
    - accent (green | blue | violet, default green): the gradient family painted
      on the incoming page. The outgoing page stays slate so the two always read
      apart.
    - corner (square | soft | round, default round): the corner radius of the
      frame the pages slide inside.

  On every default the result is identical to the original: Dashboard sliding
  out, a teal to green Analytics sliding in, inside a 30px rounded frame.
-->

<div
  class="hf-transition-page-slide"
  data-composition-variables='[
    { "id": "label_a", "type": "string", "role": "content", "label": "Outgoing label", "description": "Label printed on the page that slides out.", "default": "Dashboard" },
    { "id": "label_b", "type": "string", "role": "content", "label": "Incoming label", "description": "Label printed on the page that slides in.", "default": "Analytics" },
    { "id": "accent", "type": "enum", "role": "style", "label": "Accent", "description": "Gradient family painted on the incoming page. The outgoing page stays slate.", "default": "green", "options": [{ "value": "green", "label": "Green" }, { "value": "blue", "label": "Blue" }, { "value": "violet", "label": "Violet" }] },
    { "id": "corner", "type": "enum", "role": "style", "label": "Corner", "description": "Corner radius of the frame the pages slide inside.", "default": "round", "options": [{ "value": "square", "label": "Square" }, { "value": "soft", "label": "Soft" }, { "value": "round", "label": "Round" }] }
  ]'
>
  <section class="hf-transition-page old"><span>Dashboard</span></section>
  <section class="hf-transition-page new"><span>Analytics</span></section>
</div>

<style>
  .hf-transition-page-slide {
    position: relative;
    width: 560px;
    height: 320px;
    overflow: hidden;
    border-radius: var(--hf-page-radius, 30px);
    background: #111827;
    box-shadow: 0 28px 90px rgba(0, 0, 0, 0.22);
    font-family: Inter, system-ui, sans-serif;
  }
  .hf-transition-page {
    position: absolute;
    inset: 0;
    display: grid;
    place-items: center;
  }
  .hf-transition-page span {
    padding: 14px 20px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.14);
    color: #ffffff;
    font-size: 28px;
    font-weight: 900;
  }
  .hf-transition-page.old {
    background: linear-gradient(135deg, #0f172a, #334155);
  }
  .hf-transition-page.new {
    background: linear-gradient(135deg, var(--hf-page-from, #155e75), var(--hf-page-to, #10b981));
  }
</style>

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

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

    // Unrecognised overrides return to their declared defaults.
    var accents = {
      green: { from: "#155e75", to: "#10b981" },
      blue: { from: "#1e3a8a", to: "#38bdf8" },
      violet: { from: "#4c1d95", to: "#a78bfa" },
    };
    var corners = { square: "0px", soft: "14px", round: "30px" };

    function text(value, fallback) {
      return typeof value === "string" && value !== "" ? value : fallback;
    }
    function pick(table, value, fallback) {
      return Object.prototype.hasOwnProperty.call(table, value) ? value : fallback;
    }

    var labelA = text(vars.label_a, "Dashboard");
    var labelB = text(vars.label_b, "Analytics");
    var accent = accents[pick(accents, vars.accent, "green")];
    var corner = corners[pick(corners, vars.corner, "round")];

    var roots = document.querySelectorAll(".hf-transition-page-slide");
    for (var i = 0; i < roots.length; i += 1) {
      var root = roots[i];
      root.style.setProperty("--hf-page-radius", corner);
      root.style.setProperty("--hf-page-from", accent.from);
      root.style.setProperty("--hf-page-to", accent.to);
      var oldLabel = root.querySelector(".hf-transition-page.old span");
      var newLabel = root.querySelector(".hf-transition-page.new span");
      if (oldLabel) oldLabel.textContent = labelA;
      if (newLabel) newLabel.textContent = labelB;
    }
  })();
</script>

<!--
  Timeline integration:
  tl.fromTo('.hf-transition-page-slide', { opacity: 0, y: 24 }, { opacity: 1, y: 0, duration: 0.3, ease: 'power2.out' }, 0.25);
  tl.fromTo('.hf-transition-page.new', { xPercent: 100 }, { xPercent: 0, duration: 0.74, ease: 'power3.inOut' }, 0.78);
  tl.to('.hf-transition-page.old', { xPercent: -28, scale: 0.94, duration: 0.74, ease: 'power3.inOut' }, 0.78);
  tl.fromTo('.hf-transition-page.new span', { y: 24, opacity: 0 }, { y: 0, opacity: 1, duration: 0.28, ease: 'power2.out' }, 1.24);
-->