> ## Documentation Index
> Fetch the complete documentation index at: https://hyperframes-fix-nested-composition-media-inpoint.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Comparison Split

> Two full-bleed panels compare before and after states as a persistent divider wipes the vivid after layer over the muted before layer and rests at a configurable split.

export const VariablesExplorer = ({previewSrc, compositionId, compositionSrc, variables, children}) => {
  const SHIKI = {
    punct: {
      color: "rgb(31, 35, 40)",
      "--shiki-dark": "#808080"
    },
    tag: {
      color: "rgb(17, 99, 41)",
      "--shiki-dark": "#569CD6"
    },
    attr: {
      color: "rgb(5, 80, 174)",
      "--shiki-dark": "#9CDCFE"
    },
    equals: {
      color: "rgb(31, 35, 40)",
      "--shiki-dark": "#D4D4D4"
    },
    value: {
      color: "rgb(10, 48, 105)",
      "--shiki-dark": "#CE9178"
    }
  };
  const CSS = `
.hf-ve {
  --ve-fg: #18181b;
  --ve-muted: #71717a;
  --ve-line: #e4e4e7;
  --ve-surface: #ffffff;
  --ve-sunken: #fafafa;
  --ve-hover: #f4f4f5;
  --ve-on-bg: #18181b;
  --ve-on-fg: #ffffff;
  --ve-ring: rgba(24, 24, 27, 0.14);
  --ve-danger: #b42318;
}
:where(html.dark) .hf-ve {
  --ve-fg: #f4f4f5;
  --ve-muted: #a1a1aa;
  --ve-line: #27272a;
  --ve-surface: #18181b;
  --ve-sunken: #131316;
  --ve-hover: #27272a;
  --ve-on-bg: #f4f4f5;
  --ve-on-fg: #18181b;
  --ve-ring: rgba(244, 244, 245, 0.2);
  --ve-danger: #ff9d95;
}

.hf-ve-tabs {
  display: inline-flex;
  gap: 2px;
  padding: 3px;
  border: 1px solid var(--ve-line);
  border-radius: 9999px;
  background: var(--ve-sunken);
}
.hf-ve-tab {
  padding: 4px 12px;
  border-radius: 9999px;
  font-size: 12px;
  font-weight: 500;
  color: var(--ve-muted);
  background: transparent;
}
.hf-ve-tab[data-on="true"] {
  color: var(--ve-fg);
  background: var(--ve-surface);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.08);
}
.hf-ve-tab:hover:not([data-on="true"]) { color: var(--ve-fg); }

/* Not a grid. A grid row is as tall as its tallest cell, so a five-line snippet
   sat in the preview's 16:9 box with 300px of dead area under it. The inactive
   pane is taken out of flow instead — and stretches left/right rather than to
   inset 0, so the iframe keeps its own height. An iframe resized on every tab
   switch reflows the composition running inside it. */
.hf-ve-frame { position: relative; }
.hf-ve-cell { min-width: 0; }
.hf-ve-cell[data-on="false"] {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  visibility: hidden;
  pointer-events: none;
}
.hf-ve-preview {
  overflow: hidden;
  border: 1px solid var(--ve-line);
  border-radius: 12px;
}
/* CodeBlock carries the page margins (mt-5 mb-8) that separate it from prose,
   which is dead space inside a tab. Element plus two classes out-specifies a
   Tailwind utility without !important. */
.hf-ve-cell > div.code-block { margin: 0; }
/* The snippet wraps; the source does not.
   A value the reader has to read in full should not hide half of itself off the
   right edge, so the snippet pane wraps — what \`\`\`html wrap does for a fence.
   The width reset is the half that matters: the block's own <code> is sized to
   max-content, and content that never meets an edge never wraps.
   Source is left to scroll sideways like every other code block on the site.
   Wrapping it breaks its indentation, and a comment paragraph re-flowed to a
   narrow column reads worse than one the reader can scroll. */
.hf-ve-snippet .shiki,
.hf-ve-snippet .shiki code {
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}
/* A composition source runs to several hundred lines, and an un-capped tab
   pushes the Customize panel off the screen. The cap goes on the scroll box
   rather than the block, so the filename and its copy button stay put; and it
   is a max-height, so a short source still hugs its own content and the dead
   area under it stays gone. */
.hf-ve-cell .code-block pre {
  max-height: 460px;
  overflow: auto;
}
/* Four classes deep because the rule being answered is three
   (\`html:not(.dark) .codeblock-light pre.shiki code\`), and a shorter selector
   silently loses to it. */
.hf-ve .hf-ve-snippet .code-block pre.shiki code {
  width: auto;
  min-width: 0;
}

.hf-ve-panel {
  margin-top: 12px;
  border: 1px solid var(--ve-line);
  border-radius: 12px;
}
.hf-ve-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 16px;
  border-bottom: 1px solid var(--ve-line);
}
.hf-ve-title {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ve-muted);
}
.hf-ve-grid {
  display: grid;
  gap: 16px 28px;
  padding: 16px;
}
@media (min-width: 640px) {
  .hf-ve-grid { grid-template-columns: 1fr 1fr; }
}
.hf-ve-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 6px;
}
.hf-ve-label { font-size: 14px; font-weight: 500; color: var(--ve-fg); }
.hf-ve-value {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  color: var(--ve-muted);
}
.hf-ve-desc {
  margin: 6px 0 0;
  font-size: 12px;
  line-height: 1.45;
  color: var(--ve-muted);
}

.hf-ve-btn {
  padding: 4px 10px;
  border: 1px solid transparent;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 500;
  color: var(--ve-muted);
  background: transparent;
}
.hf-ve-btn:hover:not(:disabled) { color: var(--ve-fg); background: var(--ve-hover); }
.hf-ve-btn:disabled { opacity: 0.4; cursor: default; }

.hf-ve-field {
  width: 100%;
  height: 36px;
  padding: 0 12px;
  border: 1px solid var(--ve-line);
  border-radius: 8px;
  font-size: 14px;
  line-height: 1.4;
  color: var(--ve-fg);
  background: var(--ve-surface);
}
.hf-ve-field::placeholder { color: var(--ve-muted); }
.hf-ve-mono { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 13px; }

/* Focus, once, for every control here. A ring outside the border rather than a
   border colour alone: the border already carries the resting state, so
   recolouring it is a change a reader can miss. Nothing shifts, because the
   ring is a shadow. :focus-visible, so a pointer click does not light it up. */
.hf-ve-field:focus-visible,
.hf-ve-seg-btn:focus-visible,
.hf-ve-tab:focus-visible,
.hf-ve-btn:focus-visible,
.hf-ve-switch:focus-visible,
.hf-ve-swatch:focus-visible {
  outline: none;
  border-color: var(--ve-on-bg);
  box-shadow: 0 0 0 3px var(--ve-ring);
}
/* A range is a track, and ringing the track rings a pill the width of the
   panel. The thumb is the part that has focus, so the thumb is what says so. */
.hf-ve-range:focus-visible { outline: none; }
.hf-ve-range:focus-visible::-webkit-slider-thumb { box-shadow: 0 0 0 4px var(--ve-ring); }
.hf-ve-range:focus-visible::-moz-range-thumb { box-shadow: 0 0 0 4px var(--ve-ring); }
/* Safari still fires :focus for a click on a button, so the pair is kept. */
.hf-ve-field:focus { outline: none; border-color: var(--ve-on-bg); }

/* The enum branch above sends anything past four options here. No shipped item
   does today (every enum in the registry has two to four), so this is styled to
   the point of not looking foreign and no further — the chevron is one neutral
   grey rather than a per-theme pair, because a data URI cannot read a token. */
.hf-ve-select {
  appearance: none;
  -webkit-appearance: none;
  padding-right: 34px;
  background-image: url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='none' stroke='%2389898f' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m4 6 4 4 4-4'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
  cursor: pointer;
}

.hf-ve-seg {
  display: flex;
  padding: 2px;
  border: 1px solid var(--ve-line);
  border-radius: 8px;
}
.hf-ve-seg-btn {
  flex: 1;
  padding: 4px 8px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 500;
  color: var(--ve-muted);
  background: transparent;
}
.hf-ve-seg-btn:hover:not([data-on="true"]) { color: var(--ve-fg); background: var(--ve-hover); }
.hf-ve-seg-btn[data-on="true"] { color: var(--ve-on-fg); background: var(--ve-on-bg); }

/* A range, rebuilt. \`accent-color\` alone leaves the platform's hairline track,
   which reads as an unstyled browser part next to everything else here. Each
   engine names its parts differently and shares none of them, so the same
   track and thumb are written twice; a selector either engine cannot parse
   drops the whole rule, which is why they are never grouped. */
.hf-ve-range {
  width: 100%;
  height: 20px;
  appearance: none;
  -webkit-appearance: none;
  border: 0;
  border-radius: 9999px;
  background: transparent;
  cursor: pointer;
}
/* --ve-fill is set per render: painting progress on a native track means a
   two-stop gradient, and only the component knows where the value sits. */
.hf-ve-range::-webkit-slider-runnable-track {
  height: 6px;
  border-radius: 9999px;
  background: linear-gradient(
    to right,
    var(--ve-on-bg) var(--ve-fill, 0%),
    var(--ve-line) var(--ve-fill, 0%)
  );
}
.hf-ve-range::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  margin-top: -5px;
  border: 2px solid var(--ve-on-bg);
  border-radius: 9999px;
  background: var(--ve-surface);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.14);
}
.hf-ve-range::-moz-range-track { height: 6px; border-radius: 9999px; background: var(--ve-line); }
.hf-ve-range::-moz-range-progress { height: 6px; border-radius: 9999px; background: var(--ve-on-bg); }
.hf-ve-range::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border: 2px solid var(--ve-on-bg);
  border-radius: 9999px;
  background: var(--ve-surface);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.14);
}
/* Hover reads on the part being aimed at rather than on the whole strip: a
   track that darkens under the pointer says "click me and the thumb comes
   here", which is what a native range actually does. */
.hf-ve-range:hover::-webkit-slider-thumb { border-color: var(--ve-fg); }
.hf-ve-range:hover::-moz-range-thumb { border-color: var(--ve-fg); }

/* The number control, and the three things it used to leave unsaid.
 *
 * It could not say where the range ends, so a reader dragging \`stroke_width\`
 * had no idea whether 12 was nearly nothing or nearly everything: the ends now
 * carry min and max.
 *
 * It could not say where the author left the knob, which is the one reference
 * point a panel built around deviating from the author's choice needs: a mark
 * on the track is the default, and a double click puts the value back on it.
 *
 * And it printed the value in the label row, a fixed distance from a thumb that
 * moves, so reading a drag meant looking in two places at once. The value rides
 * the thumb instead.
 *
 * Still a real <input type="range">. Every custom slider on the web reimplements
 * keyboard stepping, touch, and the screen-reader contract, and most of them do
 * one of the three badly; none of what is added here needed the element
 * replaced. Nothing moves that a finger is not moving: the value tracks the
 * pointer because it is the pointer's own readout, and the only transition is
 * the colour one every other control here shares. */
.hf-ve-slider {
  display: grid;
  gap: 1px;
}
.hf-ve-ruler {
  position: relative;
  height: 17px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  line-height: 17px;
  color: var(--ve-muted);
}
.hf-ve-bound {
  position: absolute;
  top: 0;
}
.hf-ve-bound[data-end="min"] { left: 0; }
.hf-ve-bound[data-end="max"] { right: 0; }
/* An end steps aside rather than being overprinted by the value arriving on
   top of it. Visibility, not opacity: there is no fade here, the label is
   either the thing being read or it is out of the way. */
.hf-ve-ruler[data-near="min"] .hf-ve-bound[data-end="min"],
.hf-ve-ruler[data-near="max"] .hf-ve-bound[data-end="max"] {
  visibility: hidden;
}
/* translateX is centring, not motion: the readout is as wide as its own digits
   and has to hang half of that either side of the thumb. */
.hf-ve-readout {
  position: absolute;
  top: 0;
  left: calc(var(--ve-fill, 0%) + var(--ve-fill-nudge, 0px));
  transform: translateX(-50%);
  color: var(--ve-fg);
  font-weight: 600;
  white-space: nowrap;
}
.hf-ve-track {
  position: relative;
  display: block;
}
.hf-ve-range { display: block; }
.hf-ve-default {
  position: absolute;
  top: 5px;
  left: calc(var(--ve-default, 50%) + var(--ve-default-nudge, 0px));
  width: 2px;
  height: 10px;
  margin-left: -1px;
  border-radius: 1px;
  background: var(--ve-muted);
  pointer-events: none;
}

/* A switch, for the boolean type. It used to fall through to the text input at
   the end of control(), which asked the reader to type the word "true". */
.hf-ve-switch {
  display: inline-flex;
  align-items: center;
  width: 40px;
  height: 24px;
  padding: 2px;
  border: 1px solid var(--ve-line);
  border-radius: 9999px;
  background: var(--ve-sunken);
  cursor: pointer;
}
.hf-ve-switch[data-on="true"] { border-color: var(--ve-on-bg); background: var(--ve-on-bg); }
.hf-ve-switch-dot {
  width: 18px;
  height: 18px;
  border-radius: 9999px;
  background: var(--ve-surface);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.18);
}
.hf-ve-switch[data-on="true"] .hf-ve-switch-dot {
  background: var(--ve-on-fg);
  transform: translateX(16px);
}

/* The SVG import control: the same text field, with a way to fill it.
 *
 * The whole block is the drop target, not just the field, so a file let go over
 * the button lands too. It says so by taking the same border colour a focused
 * field takes, which is the one feedback channel this panel has left.
 *
 * A bare <input type="file"> is unlabelled, unstyleable and reads as "No file
 * chosen" next to controls that carry their own value, so the real input is
 * taken out of the layout and the tab order and a button in front of it is what
 * a reader sees and what a keyboard reaches. Hidden with size and opacity
 * rather than display:none, because an input that is not rendered at all is one
 * some browsers decline to open a picker for. */
.hf-ve-drop {
  display: grid;
  gap: 8px;
}
.hf-ve-drop[data-over="true"] .hf-ve-dropzone {
  border-color: var(--ve-on-bg);
  border-style: solid;
}

/* The import is the action almost everyone wants: a reader arrives with a
   shape, not with path data. A dashed target reads as "put a file here" on
   sight, where a button beneath a field of coordinates read as an afterthought
   to the coordinates. */
.hf-ve-dropzone {
  display: grid;
  justify-items: center;
  gap: 6px;
  padding: 18px 12px;
  border: 1px dashed var(--ve-line);
  border-radius: 10px;
  background: var(--ve-surface);
  text-align: center;
}
.hf-ve-dropzone .hf-ve-btn {
  padding: 7px 16px;
  font-size: 13px;
  color: var(--ve-fg);
  border-color: var(--ve-line);
  background: var(--ve-bg);
}
.hf-ve-dropzone .hf-ve-btn:hover:not(:disabled) { background: var(--ve-hover); }

/* Path data stays reachable, but a reader has to ask for it. A native details
   element rather than our own toggle, so it opens with the keyboard and is
   announced as expandable without any wiring. */
.hf-ve-advanced > summary {
  font-size: 12px;
  color: var(--ve-muted);
  cursor: pointer;
  list-style: none;
  padding: 2px 0;
}
.hf-ve-advanced > summary::-webkit-details-marker { display: none; }
.hf-ve-advanced > summary::before { content: "▸ "; }
.hf-ve-advanced[open] > summary::before { content: "▾ "; }
.hf-ve-advanced > summary:hover { color: var(--ve-fg); }
.hf-ve-advanced .hf-ve-field { margin-top: 6px; }
.hf-ve-file {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}
.hf-ve-note {
  margin: 0;
  min-width: 0;
  font-size: 12px;
  line-height: 1.4;
  color: var(--ve-muted);
}
.hf-ve-note[data-tone="error"] { color: var(--ve-danger); }
.hf-ve-note[data-tone="ok"] { color: var(--ve-fg); }

.hf-ve-swatch {
  width: 40px;
  height: 32px;
  flex-shrink: 0;
  padding: 2px;
  border: 1px solid var(--ve-line);
  border-radius: 8px;
  background: var(--ve-surface);
  cursor: pointer;
}

/* Nothing here moves.
 *
 * A press-down scale on every button and field, a scale-in on the tab panes, a
 * springing switch knob and a growing slider thumb were all flourish: the
 * control had already told you what it did by changing colour, and the motion
 * was a second, slower answer to a question already settled. What is left is
 * one colour transition, short enough to read as immediate and long enough not
 * to flicker. A control here may change colour; it does not move.
 *
 * Which is also why there is no prefers-reduced-motion block any more. There is
 * no motion left to reduce. */
.hf-ve-tint {
  transition:
    background-color 100ms ease,
    border-color 100ms ease,
    color 100ms ease;
}
`;
  const isSvgPathData = value => typeof value === "string" && (/^\s*[Mm]\s*-?[\d.]/).test(value);
  const parsePathData = d => {
    const source = String(d);
    const arity = {
      M: 2,
      L: 2,
      H: 1,
      V: 1,
      C: 6,
      S: 4,
      Q: 4,
      T: 2,
      A: 7,
      Z: 0
    };
    const commands = [];
    let at = 0;
    let code = "";
    const separator = () => {
      while (at < source.length && (/[\s,]/).test(source[at])) at += 1;
    };
    const digits = () => {
      while (at < source.length && source[at] >= "0" && source[at] <= "9") at += 1;
    };
    const number = () => {
      separator();
      const start = at;
      if (source[at] === "+" || source[at] === "-") at += 1;
      digits();
      if (source[at] === ".") {
        at += 1;
        digits();
      }
      if (source[at] === "e" || source[at] === "E") {
        at += 1;
        if (source[at] === "+" || source[at] === "-") at += 1;
        digits();
      }
      const text = source.slice(start, at);
      const value = Number(text);
      if (text === "" || !Number.isFinite(value)) {
        throw new Error(`expected a number at character ${start + 1}`);
      }
      return value;
    };
    const flag = () => {
      separator();
      const character = source[at];
      if (character !== "0" && character !== "1") {
        throw new Error(`expected an arc flag at character ${at + 1}`);
      }
      at += 1;
      return Number(character);
    };
    separator();
    while (at < source.length) {
      const character = source[at];
      if ((/[a-zA-Z]/).test(character)) {
        if (arity[character.toUpperCase()] === undefined) {
          throw new Error(`unknown command "${character}"`);
        }
        code = character;
        at += 1;
      } else if (code === "") {
        throw new Error("path data must open with a command");
      } else if (code === "M" || code === "m") {
        code = code === "M" ? "L" : "l";
      } else if (code === "Z" || code === "z") {
        throw new Error(`expected a command at character ${at + 1}`);
      }
      const letter = code.toUpperCase();
      const args = [];
      if (letter === "A") {
        args.push(number(), number(), number(), flag(), flag(), number(), number());
      } else {
        for (let taken = 0; taken < arity[letter]; taken += 1) args.push(number());
      }
      commands.push({
        code,
        args
      });
      separator();
    }
    if (commands.length === 0) throw new Error("path data is empty");
    return commands;
  };
  const normalisePathData = commands => {
    const out = [];
    let x = 0;
    let y = 0;
    let startX = 0;
    let startY = 0;
    let cubicControl = null;
    let quadraticControl = null;
    for (const {code, args} of commands) {
      const letter = code.toUpperCase();
      const relative = code !== letter;
      const dx = relative ? x : 0;
      const dy = relative ? y : 0;
      const pairs = values => {
        const mapped = [];
        for (let index = 0; index + 1 < values.length; index += 2) {
          mapped.push(values[index] + dx, values[index + 1] + dy);
        }
        return mapped;
      };
      let nextCubic = null;
      let nextQuadratic = null;
      if (letter === "M") {
        const [px, py] = pairs(args);
        out.push({
          code: "M",
          args: [px, py]
        });
        x = px;
        y = py;
        startX = px;
        startY = py;
      } else if (letter === "L") {
        const [px, py] = pairs(args);
        out.push({
          code: "L",
          args: [px, py]
        });
        x = px;
        y = py;
      } else if (letter === "H") {
        x = args[0] + dx;
        out.push({
          code: "L",
          args: [x, y]
        });
      } else if (letter === "V") {
        y = args[0] + dy;
        out.push({
          code: "L",
          args: [x, y]
        });
      } else if (letter === "C") {
        const points = pairs(args);
        out.push({
          code: "C",
          args: points
        });
        nextCubic = [points[2], points[3]];
        x = points[4];
        y = points[5];
      } else if (letter === "S") {
        const points = pairs(args);
        const first = cubicControl ? [2 * x - cubicControl[0], 2 * y - cubicControl[1]] : [x, y];
        out.push({
          code: "C",
          args: [...first, ...points]
        });
        nextCubic = [points[0], points[1]];
        x = points[2];
        y = points[3];
      } else if (letter === "Q") {
        const points = pairs(args);
        out.push({
          code: "Q",
          args: points
        });
        nextQuadratic = [points[0], points[1]];
        x = points[2];
        y = points[3];
      } else if (letter === "T") {
        const points = pairs(args);
        const control = quadraticControl ? [2 * x - quadraticControl[0], 2 * y - quadraticControl[1]] : [x, y];
        out.push({
          code: "Q",
          args: [...control, ...points]
        });
        nextQuadratic = control;
        x = points[0];
        y = points[1];
      } else if (letter === "A") {
        const endX = args[5] + dx;
        const endY = args[6] + dy;
        out.push(...arcToCubics(x, y, args[0], args[1], args[2], args[3], args[4], endX, endY));
        x = endX;
        y = endY;
      } else if (letter === "Z") {
        out.push({
          code: "Z",
          args: []
        });
        x = startX;
        y = startY;
      }
      cubicControl = nextCubic;
      quadraticControl = nextQuadratic;
    }
    return out;
  };
  const arcToCubics = (x1, y1, rx, ry, rotation, largeArc, sweep, x2, y2) => {
    if (x1 === x2 && y1 === y2) return [];
    let radiusX = Math.abs(rx);
    let radiusY = Math.abs(ry);
    if (radiusX === 0 || radiusY === 0) return [{
      code: "L",
      args: [x2, y2]
    }];
    const phi = rotation * Math.PI / 180;
    const cosPhi = Math.cos(phi);
    const sinPhi = Math.sin(phi);
    const midX = (x1 - x2) / 2;
    const midY = (y1 - y2) / 2;
    const primeX = cosPhi * midX + sinPhi * midY;
    const primeY = -sinPhi * midX + cosPhi * midY;
    const oversize = primeX * primeX / (radiusX * radiusX) + primeY * primeY / (radiusY * radiusY);
    if (oversize > 1) {
      const grow = Math.sqrt(oversize);
      radiusX *= grow;
      radiusY *= grow;
    }
    const denominator = radiusX * radiusX * primeY * primeY + radiusY * radiusY * primeX * primeX;
    const numerator = radiusX * radiusX * radiusY * radiusY - radiusX * radiusX * primeY * primeY - radiusY * radiusY * primeX * primeX;
    const factor = (largeArc === sweep ? -1 : 1) * Math.sqrt(Math.max(0, numerator) / denominator);
    const centrePrimeX = factor * radiusX * primeY / radiusY;
    const centrePrimeY = -factor * radiusY * primeX / radiusX;
    const centreX = cosPhi * centrePrimeX - sinPhi * centrePrimeY + (x1 + x2) / 2;
    const centreY = sinPhi * centrePrimeX + cosPhi * centrePrimeY + (y1 + y2) / 2;
    const angle = (ux, uy, vx, vy) => {
      const length = Math.hypot(ux, uy) * Math.hypot(vx, vy);
      const cosine = length === 0 ? 1 : Math.min(1, Math.max(-1, (ux * vx + uy * vy) / length));
      return (ux * vy - uy * vx < 0 ? -1 : 1) * Math.acos(cosine);
    };
    const fromX = (primeX - centrePrimeX) / radiusX;
    const fromY = (primeY - centrePrimeY) / radiusY;
    const toX = (-primeX - centrePrimeX) / radiusX;
    const toY = (-primeY - centrePrimeY) / radiusY;
    const start = angle(1, 0, fromX, fromY);
    let sweptAngle = angle(fromX, fromY, toX, toY);
    if (!sweep && sweptAngle > 0) sweptAngle -= 2 * Math.PI;
    if (sweep && sweptAngle < 0) sweptAngle += 2 * Math.PI;
    const steps = Math.max(1, Math.ceil(Math.abs(sweptAngle) / (Math.PI / 2)));
    const step = sweptAngle / steps;
    const handle = 4 / 3 * Math.tan(step / 4);
    const at = t => [centreX + radiusX * Math.cos(t) * cosPhi - radiusY * Math.sin(t) * sinPhi, centreY + radiusX * Math.cos(t) * sinPhi + radiusY * Math.sin(t) * cosPhi];
    const slope = t => [-radiusX * Math.sin(t) * cosPhi - radiusY * Math.cos(t) * sinPhi, -radiusX * Math.sin(t) * sinPhi + radiusY * Math.cos(t) * cosPhi];
    const out = [];
    for (let index = 0; index < steps; index += 1) {
      const from = start + index * step;
      const to = from + step;
      const [ax, ay] = at(from);
      const [bx, by] = at(to);
      const [aSlopeX, aSlopeY] = slope(from);
      const [bSlopeX, bSlopeY] = slope(to);
      out.push({
        code: "C",
        args: [ax + handle * aSlopeX, ay + handle * aSlopeY, bx - handle * bSlopeX, by - handle * bSlopeY, bx, by]
      });
    }
    const last = out[out.length - 1];
    last.args[4] = x2;
    last.args[5] = y2;
    return out;
  };
  const transformPathData = (segments, matrix) => segments.map(({code, args}) => {
    const moved = [];
    for (let index = 0; index + 1 < args.length; index += 2) {
      const x = args[index];
      const y = args[index + 1];
      moved.push(matrix.a * x + matrix.c * y + matrix.e, matrix.b * x + matrix.d * y + matrix.f);
    }
    return {
      code,
      args: moved
    };
  });
  const fitMatrix = (source, target) => {
    const chosen = Math.min(target.width / source.width, target.height / source.height);
    const scale = Number.isFinite(chosen) && chosen > 0 ? chosen : 1;
    return {
      a: scale,
      b: 0,
      c: 0,
      d: scale,
      e: target.x + target.width / 2 - (source.x + source.width / 2) * scale,
      f: target.y + target.height / 2 - (source.y + source.height / 2) * scale
    };
  };
  const printPathData = segments => segments.map(({code, args}) => {
    if (args.length === 0) return code;
    const numbers = args.map(value => {
      const rounded = Math.round(value * 100) / 100;
      return String(Object.is(rounded, -0) ? 0 : rounded);
    });
    return `${code} ${numbers.join(" ")}`;
  }).join(" ");
  const shapePathData = (tag, attrs) => {
    const number = (name, fallback = 0) => {
      const value = parseFloat(attrs[name]);
      return Number.isFinite(value) ? value : fallback;
    };
    if (tag === "path") {
      const d = typeof attrs.d === "string" ? attrs.d.trim() : "";
      return d === "" ? null : d;
    }
    if (tag === "rect") {
      const width = number("width");
      const height = number("height");
      if (!(width > 0) || !(height > 0)) return null;
      const x = number("x");
      const y = number("y");
      const declaredX = parseFloat(attrs.rx);
      const declaredY = parseFloat(attrs.ry);
      const rawX = Number.isFinite(declaredX) ? declaredX : declaredY;
      const rawY = Number.isFinite(declaredY) ? declaredY : declaredX;
      const rx = Math.min(Math.max(Number.isFinite(rawX) ? rawX : 0, 0), width / 2);
      const ry = Math.min(Math.max(Number.isFinite(rawY) ? rawY : 0, 0), height / 2);
      if (rx === 0 || ry === 0) {
        return `M ${x} ${y} H ${x + width} V ${y + height} H ${x} Z`;
      }
      return [`M ${x + rx} ${y}`, `H ${x + width - rx}`, `A ${rx} ${ry} 0 0 1 ${x + width} ${y + ry}`, `V ${y + height - ry}`, `A ${rx} ${ry} 0 0 1 ${x + width - rx} ${y + height}`, `H ${x + rx}`, `A ${rx} ${ry} 0 0 1 ${x} ${y + height - ry}`, `V ${y + ry}`, `A ${rx} ${ry} 0 0 1 ${x + rx} ${y}`, "Z"].join(" ");
    }
    if (tag === "circle" || tag === "ellipse") {
      const rx = tag === "circle" ? number("r") : number("rx");
      const ry = tag === "circle" ? number("r") : number("ry");
      if (!(rx > 0) || !(ry > 0)) return null;
      const cx = number("cx");
      const cy = number("cy");
      return [`M ${cx - rx} ${cy}`, `A ${rx} ${ry} 0 1 0 ${cx + rx} ${cy}`, `A ${rx} ${ry} 0 1 0 ${cx - rx} ${cy}`, "Z"].join(" ");
    }
    if (tag === "line") {
      const x1 = number("x1");
      const y1 = number("y1");
      const x2 = number("x2");
      const y2 = number("y2");
      if (x1 === x2 && y1 === y2) return null;
      return `M ${x1} ${y1} L ${x2} ${y2}`;
    }
    if (tag === "polyline" || tag === "polygon") {
      const values = String(attrs.points ?? "").trim().split(/[\s,]+/).map(Number).filter(value => Number.isFinite(value));
      if (values.length < 4) return null;
      const steps = [`M ${values[0]} ${values[1]}`];
      for (let index = 2; index + 1 < values.length; index += 2) {
        steps.push(`L ${values[index]} ${values[index + 1]}`);
      }
      if (tag === "polygon") steps.push("Z");
      return steps.join(" ");
    }
    return null;
  };
  const svgToPathData = (svgText, targetPathData, doc = document) => {
    const NS = "http://www.w3.org/2000/svg";
    const parsed = new DOMParser().parseFromString(String(svgText), "image/svg+xml");
    if (parsed.getElementsByTagName("parsererror").length > 0 || !parsed.documentElement || parsed.documentElement.localName !== "svg") {
      throw new Error("That file is not an SVG, or its markup is malformed.");
    }
    const host = doc.createElement("div");
    host.setAttribute("aria-hidden", "true");
    host.style.cssText = "position:fixed;left:-99999px;top:0;width:600px;height:600px;overflow:hidden;";
    const svg = doc.importNode(parsed.documentElement, true);
    host.appendChild(svg);
    doc.body.appendChild(host);
    try {
      const reference = doc.createElementNS(NS, "g");
      svg.appendChild(reference);
      const rootMatrix = reference.getScreenCTM();
      const defining = ["defs", "clipPath", "mask", "symbol", "marker", "pattern"];
      const isDefinition = element => {
        for (let node = element.parentNode; node && node !== svg; node = node.parentNode) {
          if (defining.includes(node.localName)) return true;
        }
        return false;
      };
      const shapes = [...svg.querySelectorAll("path,rect,circle,ellipse,line,polyline,polygon")];
      const segments = [];
      let shapesUsed = 0;
      let firstProblem = null;
      for (const element of shapes) {
        if (isDefinition(element)) continue;
        if (doc.defaultView.getComputedStyle(element).display === "none") continue;
        const attrs = {};
        for (const attribute of element.attributes) attrs[attribute.localName] = attribute.value;
        const d = shapePathData(element.localName, attrs);
        if (d === null) continue;
        let own;
        try {
          own = normalisePathData(parsePathData(d));
        } catch (error) {
          firstProblem = firstProblem ?? error.message;
          continue;
        }
        const matrix = element.getScreenCTM();
        segments.push(...rootMatrix && matrix ? transformPathData(own, rootMatrix.inverse().multiply(matrix)) : own);
        shapesUsed += 1;
      }
      if (segments.length === 0) {
        if (firstProblem) throw new Error(`This SVG has unreadable path data: ${firstProblem}.`);
        const untraceable = ["text", "image", "use"].find(tag => svg.getElementsByTagName(tag).length > 0);
        throw new Error(untraceable ? `This SVG draws with <${untraceable}>, which has no outline to trace. Convert it to paths and try again.` : "This SVG has no shapes to import.");
      }
      const probe = doc.createElementNS(NS, "path");
      svg.appendChild(probe);
      probe.setAttribute("d", printPathData(segments));
      const source = probe.getBBox();
      if (!(source.width > 0) || !(source.height > 0)) {
        if (!(source.width > 0) && !(source.height > 0)) {
          throw new Error("This SVG's shapes have no size.");
        }
      }
      probe.setAttribute("d", String(targetPathData));
      const target = probe.getBBox();
      return {
        d: printPathData(transformPathData(segments, fitMatrix(source, target))),
        shapes: shapesUsed
      };
    } finally {
      host.remove();
    }
  };
  const granularity = value => {
    const decimals = String(value).split(".")[1];
    return decimals ? Number(`1e-${decimals.length}`) : 1;
  };
  const readout = (variable, value) => {
    if (variable.type === "number") return "";
    if (variable.type === "color") return String(value);
    if (variable.type === "enum") {
      const hit = (variable.options ?? []).find(o => o.value === value);
      return hit ? hit.label ?? hit.value : String(value);
    }
    return "";
  };
  const control = (variable, value, onChange, note, onNote, onTyping) => {
    const options = variable.options ?? [];
    if (variable.type === "enum" && options.length > 0 && options.length <= 4) {
      return <div className="hf-ve-seg">
          {options.map(o => <button key={o.value} type="button" data-on={value === o.value} aria-pressed={value === o.value} onClick={() => onChange(o.value)} className="hf-ve-seg-btn hf-ve-tint">
              {o.label ?? o.value}
            </button>)}
        </div>;
    }
    if (variable.type === "enum") {
      return <select className="hf-ve-field hf-ve-select hf-ve-tint" value={value} aria-label={variable.label ?? variable.id} onChange={e => onChange(e.target.value)}>
          {options.map(o => <option key={o.value} value={o.value}>
              {o.label ?? o.value}
            </option>)}
        </select>;
    }
    if (variable.type === "number") {
      const min = Number(variable.min);
      const max = Number(variable.max);
      const unit = variable.unit ?? "";
      const declaredStep = Number(variable.step);
      const step = declaredStep > 0 ? declaredStep : 1;
      const label = variable.label ?? variable.id;
      if (!(Number.isFinite(min) && Number.isFinite(max) && max > min)) {
        return <input type="number" className="hf-ve-field hf-ve-mono hf-ve-tint" value={value} min={Number.isFinite(min) ? min : undefined} max={Number.isFinite(max) ? max : undefined} step={declaredStep > 0 ? declaredStep : granularity(variable.default)} aria-label={label} onChange={e => {
          const next = Number(e.target.value);
          if (e.target.value !== "" && Number.isFinite(next)) onChange(next);
        }} />;
      }
      const at = n => Math.min(1, Math.max(0, (Number(n) - min) / (max - min)));
      const now = at(value);
      const authored = at(variable.default);
      const place = fraction => ({
        offset: `${fraction * 100}%`,
        nudge: `${(0.5 - fraction) * 16}px`
      });
      const value_ = place(now);
      const default_ = place(authored);
      const grain = event => {
        event.currentTarget.step = event.shiftKey ? step / 10 : step;
      };
      return <div className="hf-ve-slider" style={{
        "--ve-fill": value_.offset,
        "--ve-fill-nudge": value_.nudge,
        "--ve-default": default_.offset,
        "--ve-default-nudge": default_.nudge
      }}>
          {}
          <div className="hf-ve-ruler" data-near={now < 0.14 ? "min" : now > 0.86 ? "max" : ""} aria-hidden="true">
            <span className="hf-ve-bound" data-end="min">
              {min}
            </span>
            <span className="hf-ve-bound" data-end="max">
              {max}
            </span>
            <span className="hf-ve-readout">
              {value}
              {unit}
            </span>
          </div>
          <span className="hf-ve-track">
            <input type="range" className="hf-ve-range" min={min} max={max} step={step} value={value} aria-label={label} aria-valuetext={`${value}${unit}`} onChange={e => onChange(Number(e.target.value))} onPointerDown={grain} onKeyDown={grain} onDoubleClick={() => onChange(variable.default)} />
            {}
            {Math.abs(now - authored) > 0.04 && <span className="hf-ve-default" aria-hidden="true" />}
          </span>
        </div>;
    }
    if (variable.type === "boolean") {
      const on = value === true || value === "true";
      return <button type="button" role="switch" aria-checked={on} aria-label={variable.label ?? variable.id} data-on={on} onClick={() => onChange(!on)} className="hf-ve-switch">
          <span className="hf-ve-switch-dot" />
        </button>;
    }
    if (variable.type === "color") {
      return <div className="flex items-center gap-2">
          <input type="color" className="hf-ve-swatch hf-ve-tint" value={value} aria-label={variable.label ?? variable.id} onChange={e => onChange(e.target.value)} />
          <input type="text" className="hf-ve-field hf-ve-mono hf-ve-tint" value={value} onChange={e => onChange(e.target.value)} onFocus={() => onTyping(variable.id)} onBlur={() => onTyping(null)} onKeyDown={e => {
        if (e.key === "Enter") e.currentTarget.blur();
      }} />
        </div>;
    }
    if (isSvgPathData(variable.default)) {
      const fileId = `hf-ve-file-${variable.id}`;
      const noteId = `hf-ve-note-${variable.id}`;
      const receive = file => {
        if (!file) return;
        file.text().then(text => {
          const {d, shapes} = svgToPathData(text, variable.default);
          onChange(d);
          onNote({
            tone: "ok",
            message: `${file.name}: ${shapes} shape${shapes === 1 ? "" : "s"} scaled to fit.`
          });
        }).catch(error => onNote({
          tone: "error",
          message: error.message
        }));
      };
      return <div className="hf-ve-drop" onDragOver={event => {
        event.preventDefault();
        event.currentTarget.dataset.over = "true";
      }} onDragLeave={event => {
        event.currentTarget.dataset.over = "false";
      }} onDrop={event => {
        event.preventDefault();
        event.currentTarget.dataset.over = "false";
        receive(event.dataTransfer.files[0]);
      }}>
          {}
          <div className="hf-ve-dropzone">
            <button type="button" className="hf-ve-btn hf-ve-tint" onClick={() => document.getElementById(fileId).click()}>
              Import SVG
            </button>
            <input id={fileId} type="file" accept=".svg,image/svg+xml" className="hf-ve-file" tabIndex={-1} aria-hidden="true" onChange={event => {
        receive(event.target.files[0]);
        event.target.value = "";
      }} />
            {}
            <p id={noteId} role="status" className="hf-ve-note" data-tone={note ? note.tone : ""}>
              {note ? note.message : "Or drop one here. Scaled to fit and centred."}
            </p>
          </div>
          <details className="hf-ve-advanced">
            <summary>Path data</summary>
            <input type="text" className="hf-ve-field hf-ve-mono hf-ve-tint" value={value} aria-label={variable.label ?? variable.id} onChange={e => onChange(e.target.value)} onFocus={() => onTyping(variable.id)} onBlur={() => onTyping(null)} onKeyDown={e => {
        if (e.key === "Enter") e.currentTarget.blur();
      }} />
          </details>
        </div>;
    }
    return <input type="text" className="hf-ve-field hf-ve-tint" value={value} aria-label={variable.label ?? variable.id} onChange={e => onChange(e.target.value)} onFocus={() => onTyping(variable.id)} onBlur={() => onTyping(null)} onKeyDown={e => {
      if (e.key === "Enter") e.currentTarget.blur();
    }} />;
  };
  const variablesKey = JSON.stringify(variables);
  const defaults = useMemo(() => {
    const built = {};
    for (const v of variables) if (v.default !== undefined) built[v.id] = v.default;
    return built;
  }, [variablesKey]);
  const urlKey = `vars-${compositionId}`;
  const readFromUrl = () => {
    if (typeof window === "undefined") return {};
    try {
      const raw = new URLSearchParams(window.location.search).get(urlKey);
      if (!raw) return {};
      const parsed = JSON.parse(raw);
      if (!parsed || typeof parsed !== "object" || Array.isArray(parsed)) return {};
      const declared = new Set(variables.map(v => v.id));
      return Object.fromEntries(Object.entries(parsed).filter(([id]) => declared.has(id)));
    } catch {
      return {};
    }
  };
  const [values, setValues] = useState(() => ({
    ...defaults,
    ...readFromUrl()
  }));
  useEffect(() => {
    const fromUrl = readFromUrl();
    if (Object.keys(fromUrl).length > 0) setValues(current => ({
      ...current,
      ...fromUrl
    }));
  }, []);
  useEffect(() => {
    if (typeof window === "undefined") return;
    const changed = Object.fromEntries(Object.entries(values).filter(([id, value]) => JSON.stringify(value) !== JSON.stringify(defaults[id])));
    const url = new URL(window.location.href);
    if (Object.keys(changed).length === 0) url.searchParams.delete(urlKey); else url.searchParams.set(urlKey, JSON.stringify(changed));
    const next = url.toString();
    if (next !== window.location.href) {
      window.history.replaceState(null, "", next);
      window.dispatchEvent(new CustomEvent("hf-vars-changed"));
    }
  }, [values, defaults, urlKey]);
  const [notes, setNotes] = useState({});
  const [typing, setTyping] = useState(null);
  const posted = useRef(null);
  const [tab, setTab] = useState("preview");
  const frame = useRef(null);
  const bootstrap = ["<!doctype html><html><head><meta charset='utf-8'>", "<style>html,body{margin:0;height:100%;overflow:hidden;background:transparent}", "hyperframes-player{display:block;width:100%;height:100%}</style>", '<script src="https://cdn.jsdelivr.net/npm/@hyperframes/player@0.7/dist/hyperframes-player.global.js"></' + "script>", "</head><body><script>", "(function(){", `  var PAYLOAD = ${JSON.stringify(previewSrc)};`, `  var INITIAL = ${JSON.stringify({
    ...defaults,
    ...readFromUrl()
  })};`, "  var html = null, player = null, poll = null;", "  function withValues(source, values) {", "    var json = JSON.stringify(values);", "    var attr = json.replace(/'/g, '&#39;');", "    var out = source.replace(/\\sdata-variable-values=(?:\"[^\"]*\"|'[^']*')/gi, '');", "    out = out.replace(/(data-composition-src=)/gi, \"data-variable-values='\" + attr + \"' $1\");", "    var tag = '<' + 'script>window.__hfVariables=' + json + ';<' + '/script>';", "    return /<head[^>]*>/i.test(out)", "      ? out.replace(/<head([^>]*)>/i, '<head$1>' + tag)", "      : tag + out;", "  }", "  function arm(resumeAt) {", "    clearInterval(poll);", "    var last = -1, tries = 0, seeked = false;", "    poll = setInterval(function () {", "      if (player.ready) {", "        if (!seeked) { seeked = true; if (resumeAt > 0) player.seek(resumeAt); }", "        player.play();", "      }", "      if (seeked && player.currentTime > 0 && player.currentTime !== last) {", "        clearInterval(poll); return;", "      }", "      last = player.currentTime;", "      if (++tries > 150) clearInterval(poll);", "    }, 100);", "  }", "  function mount(values, resumeAt) {", "    if (html === null) return;", "    player.setAttribute('srcdoc', withValues(html, values));", "    arm(resumeAt || 0);", "  }", "  player = document.createElement('hyperframes-player');", "  player.setAttribute('controls', ''); player.setAttribute('muted', '');", "  document.body.appendChild(player);", "  player.addEventListener('ended', function () { player.seek(0); player.play(); });", "  fetch(PAYLOAD).then(function (r) { return r.json(); }).then(function (d) {", "    html = d.html; mount(INITIAL, 0);", "  }).catch(function (e) {", "    document.body.innerHTML = '<pre style=\"color:#f66;font:12px monospace;padding:12px\">preview unavailable: ' + e + '</pre>';", "  });", "  addEventListener('message', function (event) {", "    var values = event.data && event.data.hfVariables;", "    if (!values) return;", "    mount(values, player.currentTime || 0);", "  });", "})();", "</" + "script></body></html>"].join("");
  useEffect(() => {
    if (typing !== null) return;
    const payload = JSON.stringify(values);
    if (payload === posted.current) return;
    const timer = setTimeout(() => {
      const target = frame.current && frame.current.contentWindow;
      if (!target) return;
      posted.current = payload;
      target.postMessage({
        hfVariables: values
      }, window.location.origin);
    }, 150);
    return () => clearTimeout(timer);
  }, [values, typing]);
  const printed = JSON.stringify(values, null, 2).split("\n").join("\n  ");
  const attributes = [["data-composition-id", `"${compositionId}"`], ["data-composition-src", `"${compositionSrc}"`], ["data-variable-values", `'${printed}'`]];
  const snippetLines = [[[SHIKI.punct, "<"], [SHIKI.tag, "div"]]];
  for (const [name, literal] of attributes) {
    const [head, ...rest] = literal.split("\n");
    snippetLines.push([[SHIKI.attr, `  ${name}`], [SHIKI.equals, "="], [SHIKI.value, head]]);
    for (const line of rest) snippetLines.push([[SHIKI.value, line]]);
  }
  snippetLines.push([[SHIKI.punct, "></"], [SHIKI.tag, "div"], [SHIKI.punct, ">"]]);
  const dirty = variables.some(v => values[v.id] !== defaults[v.id]);
  const installCommand = (() => {
    const base = `npx hyperframes add ${compositionId}`;
    if (!dirty) return base;
    const changed = {};
    for (const v of variables) {
      if (JSON.stringify(values[v.id]) !== JSON.stringify(defaults[v.id])) changed[v.id] = values[v.id];
    }
    return `${base} --vars '${JSON.stringify(changed)}'`;
  })();
  const TABS = [["preview", "Preview"], ...children ? [["code", "Code"]] : [], ["snippet", "Snippet"]];
  return <div className="hf-ve not-prose my-4">
      <style dangerouslySetInnerHTML={{
    __html: CSS
  }} />

      <div className="mb-3 flex items-center gap-3">
        <div className="hf-ve-tabs">
          {TABS.map(([id, label]) => <button key={id} type="button" data-on={tab === id} aria-pressed={tab === id} onClick={() => setTab(id)} className="hf-ve-tab hf-ve-tint">
              {label}
            </button>)}
        </div>
      </div>

      {}
      <div className="hf-ve-frame">
        <div className="hf-ve-cell" data-on={tab === "preview"}>
          <iframe ref={frame} srcDoc={bootstrap} className="hf-ve-preview block aspect-video w-full" title={`${compositionId} preview`} />
        </div>
        {children && <div className="hf-ve-cell" data-on={tab === "code"}>
            {children}
          </div>}
        <div className="hf-ve-cell hf-ve-snippet" data-on={tab === "snippet"}>
          {}
          <CodeBlock filename="Terminal">
            <pre className="shiki shiki-themes github-light-default dark-plus" style={{
    backgroundColor: "rgb(255, 255, 255)",
    "--shiki-dark-bg": "#0B0C0E",
    color: "rgb(31, 35, 40)",
    "--shiki-dark": "#D4D4D4"
  }}>
              <code>
                <span className="line">
                  <span style={SHIKI.value}>{installCommand}</span>
                  {"\n"}
                </span>
              </code>
            </pre>
          </CodeBlock>
          {}
          <CodeBlock filename="index.html">
            <pre className="shiki shiki-themes github-light-default dark-plus" style={{
    backgroundColor: "rgb(255, 255, 255)",
    "--shiki-dark-bg": "#0B0C0E",
    color: "rgb(31, 35, 40)",
    "--shiki-dark": "#D4D4D4"
  }}>
              <code>
                {snippetLines.map((tokens, line) => <span key={line} className="line">
                    {tokens.map(([style, text], token) => <span key={token} style={style}>
                        {text}
                      </span>)}
                    {"\n"}
                  </span>)}
              </code>
            </pre>
          </CodeBlock>
        </div>
      </div>

      <div className="hf-ve-panel">
        <div className="hf-ve-head">
          <span className="hf-ve-title">Customize</span>
          <button type="button" onClick={() => {
    setValues(defaults);
    setNotes({});
  }} disabled={!dirty} className="hf-ve-btn hf-ve-tint">
            Reset
          </button>
        </div>
        <div className="hf-ve-grid">
          {variables.map(v => <div key={v.id}>
              <div className="hf-ve-row">
                <label className="hf-ve-label">{v.label ?? v.id}</label>
                <span className="hf-ve-value">{readout(v, values[v.id])}</span>
              </div>
              {control(v, values[v.id], next => setValues(prev => ({
    ...prev,
    [v.id]: next
  })), notes[v.id], note => setNotes(prev => ({
    ...prev,
    [v.id]: note
  })), setTyping)}
              {v.description && <p className="hf-ve-desc">{v.description}</p>}
            </div>)}
        </div>
      </div>
    </div>;
};

export const InstallCommand = ({command, item}) => {
  const [copied, setCopied] = React.useState(false);
  const [tuned, setTuned] = React.useState("");
  React.useEffect(() => {
    if (!item) return;
    const read = () => {
      try {
        const raw = new URLSearchParams(window.location.search).get(`vars-${item}`);
        if (!raw) return setTuned("");
        const parsed = JSON.parse(raw);
        if (!parsed || typeof parsed !== "object" || Array.isArray(parsed)) return setTuned("");
        if (Object.keys(parsed).length === 0) return setTuned("");
        setTuned(` --vars '${JSON.stringify(parsed)}'`);
      } catch {
        setTuned("");
      }
    };
    read();
    window.addEventListener("hf-vars-changed", read);
    window.addEventListener("popstate", read);
    return () => {
      window.removeEventListener("hf-vars-changed", read);
      window.removeEventListener("popstate", read);
    };
  }, [item]);
  const fullCommand = `${command}${tuned}`;
  const copy = async () => {
    try {
      if (navigator.clipboard && window.isSecureContext) {
        await navigator.clipboard.writeText(fullCommand);
      } else {
        const previous = document.activeElement;
        const scratch = document.createElement("textarea");
        scratch.value = fullCommand;
        scratch.setAttribute("readonly", "");
        scratch.style.position = "fixed";
        scratch.style.opacity = "0";
        document.body.appendChild(scratch);
        scratch.select();
        document.execCommand("copy");
        document.body.removeChild(scratch);
        previous?.focus?.();
      }
      setCopied(true);
      setTimeout(() => setCopied(false), 2000);
    } catch {}
  };
  return <div className="hf-install-command not-prose my-4 flex items-stretch overflow-hidden rounded-xl border border-zinc-200 bg-zinc-50 dark:border-zinc-800 dark:bg-zinc-900">
      <code className="flex-1 overflow-x-auto whitespace-nowrap border-r border-zinc-200 px-4 py-3 font-mono text-sm text-zinc-800 dark:border-zinc-800 dark:text-zinc-100">
        {fullCommand}
      </code>
      <button type="button" onClick={copy} data-copied={copied ? "true" : "false"} aria-label={`Copy ${command} to the clipboard`} className="hf-install-copy">
        <svg className="hf-install-copy-clipboard" xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 18 18" fill="none" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
          <path d="M14.25 5.25H7.25C6.14543 5.25 5.25 6.14543 5.25 7.25V14.25C5.25 15.3546 6.14543 16.25 7.25 16.25H14.25C15.3546 16.25 16.25 15.3546 16.25 14.25V7.25C16.25 6.14543 15.3546 5.25 14.25 5.25Z" />
          <path d="M2.80103 11.998L1.77203 5.07397C1.61003 3.98097 2.36403 2.96397 3.45603 2.80197L10.38 1.77297C11.313 1.63397 12.19 2.16297 12.528 3.00097" />
        </svg>
        <svg className="hf-install-copy-check" xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 18 18" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
          <path d="M2.75 9.5L6.5 13.25L15.25 4.5" />
        </svg>
      </button>
      <span className="hf-install-copy-status" role="status" aria-live="polite">
        {copied ? "Copied" : ""}
      </span>
    </div>;
};

<VariablesExplorer previewSrc="/public/catalog/components/comparison-split.json" compositionId="comparison-split" compositionSrc="compositions/components/comparison-split.html" variables={[{"id":"split","type":"number","role":"layout","label":"Split position","description":"Target resting position of the comparison divider.","default":50,"min":0,"max":100,"step":1,"unit":"%"},{"id":"orientation","type":"enum","role":"layout","label":"Orientation","description":"Axis and direction used by the comparison wipe.","default":"horizontal","options":[{"value":"horizontal","label":"Horizontal"},{"value":"vertical","label":"Vertical"}]},{"id":"labelA","type":"string","role":"content","label":"Before label","description":"Caption shown on the base before panel.","default":"Before"},{"id":"labelB","type":"string","role":"content","label":"After label","description":"Caption shown on the revealed after panel.","default":"After"}]}>
  ```html comparison-split.html theme={null}
  <!doctype html>
  <!--
    comparison-split: HyperFrames video primitive (ui-props / holdable / compare)

    Concept: two full-bleed treatments share one frame. The muted before panel
    stays fully visible as the base, while the vivid after panel wipes over it
    from the leading edge. A persistent divider marks the shared clip boundary.
    One mechanic, one job: compare two visual states.

    Compiled-from evidence: fixture + blueprint (re-filed from prove), from the
    video-primitives compare shelf.

    Use when: a scene needs a direct before-and-after comparison, a redesign
    reveal, or a visual treatment contrast that must remain readable during a
    long hold.

    Variables (declared in data-composition-variables below):
      - split (number, default 50, range 0 to 100%): target resting position.
      - orientation (horizontal | vertical, default horizontal): horizontal uses
        a vertical divider traveling left to right, vertical uses a horizontal
        divider traveling top to bottom.
      - labelA (string, default "Before"): caption on the base panel.
      - labelB (string, default "After"): caption on the revealed panel.

    Envelope (fixed IN/OUT, elastic HOLD only, never gsap.timeScale()):
      IN_BASE  = 1.40s  stage settles, then the divider wipes from 0% to split
      HOLD     = elastic = max(0, D - (IN_BASE + OUT_BASE)); deliberately still
                 so the target comparison remains easy to inspect
      OUT_BASE = 0.50s  release fade
      If D < IN_BASE + OUT_BASE, IN and OUT scale down together so IN + OUT == D
      and HOLD == 0.

    Sync point: wipe-land is fixed at WIPE_END_BASE = 1.30s inside IN. It scales
    proportionally only when the full envelope is shorter than 1.90s, and never
    moves into elastic HOLD.

    Sound cue: a soft wipe landing hook fires at wipe-land. This primitive never
    plays audio. It dispatches a bubbling `hf:sfx` CustomEvent with id
    "wipe-land-soft", so scene-level audio mixing owns playback.

    Mount contract: this file is a MOUNTABLE SUB-COMPOSITION. A host loads it via
    data-composition-src, and the runtime clones only <template> contents. All
    live styles, markup, GSAP, and timeline registration therefore live inside
    <template>. #root is styled by id, fills the host with inset:0, establishes
    the cqw/cqh container, and has no data-width or data-height. The composition
    id is the hardcoded literal "comparison-split" because mount flattening
    strips data-composition-id from the live root. Variables come from
    window.__hyperframes.getVariables(), which merges declared defaults with
    per-instance host overrides.
  -->
  <html
    lang="en"
    data-composition-variables='[
      { "id": "split", "type": "number", "role": "layout", "label": "Split position", "description": "Target resting position of the comparison divider.", "default": 50, "min": 0, "max": 100, "step": 1, "unit": "%" },
      { "id": "orientation", "type": "enum", "role": "layout", "label": "Orientation", "description": "Axis and direction used by the comparison wipe.", "default": "horizontal", "options": [{ "value": "horizontal", "label": "Horizontal" }, { "value": "vertical", "label": "Vertical" }] },
      { "id": "labelA", "type": "string", "role": "content", "label": "Before label", "description": "Caption shown on the base before panel.", "default": "Before" },
      { "id": "labelB", "type": "string", "role": "content", "label": "After label", "description": "Caption shown on the revealed after panel.", "default": "After" }
    ]'
  >
    <head>
      <!-- The mount runtime reads variables from <html>, then discards everything
           outside <template>, including this head. -->
    </head>
    <body>
      <template>
        <div id="root" data-composition-id="comparison-split" data-duration="4" data-fps="30">
          <style>
            *,
            *::before,
            *::after {
              box-sizing: border-box;
            }

            /* Root fills the host-owned box. Every internal measurement uses
               cqw/cqh, and every painted color comes from a theme token. */
            #root {
              position: absolute;
              inset: 0;
              container-type: size;
              isolation: isolate;
              overflow: hidden;
              background: var(--bg, #07111f);
              color: var(--fg, #f8fafc);
              font-family: var(--font-body, Inter, system-ui, sans-serif);
            }

            .cs-clip,
            .cs-stage,
            .cs-panel {
              position: absolute;
              inset: 0;
              width: 100%;
              height: 100%;
            }

            .cs-clip {
              overflow: hidden;
            }

            .cs-stage {
              --cs-split: 0;
              opacity: 0;
            }

            .cs-before {
              background:
                linear-gradient(
                    color-mix(in srgb, var(--border, #334155) 38%, transparent) 0.12cqw,
                    transparent 0.12cqw
                  )
                  0 0 / 5cqw 5cqw,
                linear-gradient(
                    90deg,
                    color-mix(in srgb, var(--border, #334155) 38%, transparent) 0.12cqw,
                    transparent 0.12cqw
                  )
                  0 0 / 5cqw 5cqw,
                var(--surface, #172033);
            }

            .cs-after {
              z-index: 2;
              clip-path: inset(0 calc((100 - var(--cs-split)) * 1%) 0 0);
              background: color-mix(in srgb, var(--fg, #f8fafc) 18%, var(--surface, #172033));
            }

            .cs-window {
              position: absolute;
              left: 14cqw;
              top: 18cqh;
              width: 72cqw;
              height: 64cqh;
              overflow: hidden;
              border-radius: min(3cqw, 5cqh);
              border: 0.16cqw solid var(--border, #334155);
              background: color-mix(in srgb, var(--surface, #172033) 90%, var(--muted, #94a3b8));
              box-shadow: 0 2.2cqh 6cqw color-mix(in srgb, var(--bg, #07111f) 50%, transparent);
            }

            .cs-after .cs-window {
              border-color: color-mix(in srgb, var(--fg, #f8fafc) 45%, transparent);
              background: color-mix(in srgb, var(--fg, #f8fafc) 8%, var(--surface, #172033));
              box-shadow: 0 2.2cqh 7cqw rgba(0, 0, 0, 0.18);
            }

            .cs-toolbar {
              display: flex;
              align-items: center;
              gap: var(--space-1, 1.2cqw);
              height: 12cqh;
              padding: 0 var(--space-2, 2.4cqw);
              border-bottom: 0.14cqw solid var(--border, #334155);
            }

            .cs-dot {
              width: min(2.2cqw, 3.2cqh);
              aspect-ratio: 1;
              border-radius: 50%;
              background: var(--muted, #94a3b8);
              opacity: 0.55;
            }

            .cs-after .cs-dot {
              background: var(--accent, #f8fafc);
              opacity: 1;
            }

            .cs-content {
              position: relative;
              height: 52cqh;
            }

            .cs-copy {
              position: absolute;
              left: 7cqw;
              top: 9cqh;
              width: 31cqw;
            }

            .cs-line {
              height: 2.3cqh;
              margin-bottom: var(--space-2, 2.4cqh);
              border-radius: 2cqh;
              background: var(--muted, #94a3b8);
              opacity: 0.48;
            }

            .cs-line:nth-child(1) {
              width: 94%;
            }

            .cs-line:nth-child(2) {
              width: 72%;
            }

            .cs-line:nth-child(3) {
              width: 48%;
            }

            .cs-after .cs-line {
              background: color-mix(in srgb, var(--fg, #f8fafc) 72%, transparent);
              opacity: 1;
            }

            .cs-visual {
              position: absolute;
              right: 7cqw;
              top: 7cqh;
              width: min(22cqw, 32cqh);
              aspect-ratio: 1;
              border-radius: 36% 64% 58% 42%;
              border: 0.3cqw solid var(--border, #334155);
              background: var(--muted, #94a3b8);
              opacity: 0.5;
            }

            .cs-after .cs-visual {
              border-color: color-mix(in srgb, var(--fg, #f8fafc) 45%, transparent);
              background: color-mix(in srgb, var(--fg, #f8fafc) 72%, transparent);
              box-shadow: 0 0 5cqw rgba(0, 0, 0, 0.18);
              opacity: 1;
            }

            .cs-label {
              position: absolute;
              z-index: 4;
              top: var(--space-3, 4cqh);
              padding: var(--space-1, 1.2cqh) var(--space-2, 2.2cqw);
              border: 0.14cqw solid var(--border, #334155);
              border-radius: 999cqw;
              background: var(--surface, #172033);
              color: var(--fg, #f8fafc);
              font-family: var(--font-display, Inter, system-ui, sans-serif);
              font-size: min(3cqw, 4.2cqh);
              font-weight: 700;
              letter-spacing: 0.08em;
              line-height: 1;
              text-transform: uppercase;
              white-space: nowrap;
            }

            .cs-before .cs-label {
              right: var(--space-3, 4cqw);
              color: var(--muted, #94a3b8);
            }

            .cs-after .cs-label {
              left: var(--space-3, 4cqw);
              border-color: color-mix(in srgb, var(--fg, #f8fafc) 45%, transparent);
              background: color-mix(in srgb, var(--fg, #f8fafc) 8%, var(--surface, #172033));
            }

            .cs-divider {
              position: absolute;
              z-index: 5;
              top: 0;
              bottom: 0;
              left: calc(var(--cs-split) * 1%);
              width: 0.45cqw;
              transform: translateX(-50%);
              background: var(--fg, #f8fafc);
              box-shadow:
                0 0 1.4cqw color-mix(in srgb, var(--fg, #f8fafc) 45%, transparent),
                0 0 3cqw rgba(0, 0, 0, 0.45);
              pointer-events: none;
            }

            .cs-divider::after {
              content: "";
              position: absolute;
              left: 50%;
              top: 50%;
              width: min(5cqw, 7cqh);
              aspect-ratio: 1;
              transform: translate(-50%, -50%);
              border: 0.3cqw solid var(--bg, #07111f);
              border-radius: 50%;
              background: var(--fg, #f8fafc);
              box-shadow: 0 0 2.2cqw color-mix(in srgb, var(--fg, #f8fafc) 45%, transparent);
            }

            /* INVARIANT: vertical changes only the axis mapping. The after clip
               and divider still read the same --cs-split value. */
            #root[data-orientation="vertical"] .cs-after {
              clip-path: inset(0 0 calc((100 - var(--cs-split)) * 1%) 0);
            }

            #root[data-orientation="vertical"] .cs-before .cs-label {
              top: auto;
              right: var(--space-3, 4cqw);
              bottom: var(--space-3, 4cqh);
            }

            #root[data-orientation="vertical"] .cs-divider {
              top: calc(var(--cs-split) * 1%);
              right: 0;
              bottom: auto;
              left: 0;
              width: 100%;
              height: 0.45cqh;
              transform: translateY(-50%);
            }
          </style>

          <div
            id="comparison-split-clip"
            class="cs-clip clip"
            data-start="0"
            data-duration="4"
            data-track-index="0"
          >
            <div class="cs-stage">
              <section class="cs-panel cs-before" aria-label="Before panel">
                <div class="cs-label"></div>
                <div class="cs-window">
                  <div class="cs-toolbar">
                    <span class="cs-dot"></span>
                    <span class="cs-dot"></span>
                    <span class="cs-dot"></span>
                  </div>
                  <div class="cs-content">
                    <div class="cs-copy">
                      <div class="cs-line"></div>
                      <div class="cs-line"></div>
                      <div class="cs-line"></div>
                    </div>
                    <div class="cs-visual"></div>
                  </div>
                </div>
              </section>

              <section class="cs-panel cs-after" aria-label="After panel">
                <div class="cs-label"></div>
                <div class="cs-window">
                  <div class="cs-toolbar">
                    <span class="cs-dot"></span>
                    <span class="cs-dot"></span>
                    <span class="cs-dot"></span>
                  </div>
                  <div class="cs-content">
                    <div class="cs-copy">
                      <div class="cs-line"></div>
                      <div class="cs-line"></div>
                      <div class="cs-line"></div>
                    </div>
                    <div class="cs-visual"></div>
                  </div>
                </div>
              </section>

              <div class="cs-divider" aria-hidden="true"></div>
            </div>
          </div>

          <script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
          <script>
            (function () {
              "use strict";

              var root = document.getElementById("root");
              // Hardcoded because mount flattening strips data-composition-id
              // from the live root before this timeline registers.
              var compositionId = "comparison-split";
              var stage = root.querySelector(".cs-stage");
              var labelAEl = root.querySelector(".cs-before .cs-label");
              var labelBEl = root.querySelector(".cs-after .cs-label");

              // EDIT ZONE: declarations above and registry metadata change
              // together. This API owns defaults plus per-instance overrides.
              var vars =
                window.__hyperframes && window.__hyperframes.getVariables
                  ? window.__hyperframes.getVariables()
                  : {};

              var rawSplit = vars.split == null ? 50 : Number(vars.split);
              // INVARIANT: split always clamps into the declared 0 to 100 range.
              var splitPct = Number.isFinite(rawSplit) ? Math.max(0, Math.min(100, rawSplit)) : 50;
              // INVARIANT: only horizontal or vertical reaches the renderer.
              var orientation = vars.orientation === "vertical" ? "vertical" : "horizontal";
              var labelAText = vars.labelA == null ? "" : String(vars.labelA);
              var labelBText = vars.labelB == null ? "" : String(vars.labelB);

              root.setAttribute("data-orientation", orientation);
              labelAEl.textContent = labelAText;
              labelBEl.textContent = labelBText;

              // RETIME RANGE: fixed IN and OUT scale together only when D is too
              // short. HOLD is the sole elastic phase. Never use timeScale().
              var IN_BASE = 1.4;
              var OUT_BASE = 0.5;
              var STAGE_IN_BASE = 0.32;
              var WIPE_AT_BASE = 0.25;
              var WIPE_DURATION_BASE = 1.05;
              var WIPE_END_BASE = WIPE_AT_BASE + WIPE_DURATION_BASE;

              var duration = Math.max(0.001, parseFloat(root.dataset.duration || "4"));
              var totalBase = IN_BASE + OUT_BASE;
              var scale = duration < totalBase ? duration / totalBase : 1;
              var IN = IN_BASE * scale;
              var OUT = OUT_BASE * scale;
              var STAGE_IN = STAGE_IN_BASE * scale;
              var WIPE_AT = WIPE_AT_BASE * scale;
              var WIPE_DURATION = WIPE_DURATION_BASE * scale;
              var WIPE_END = WIPE_END_BASE * scale;
              var HOLD = Math.max(0, duration - (IN + OUT));
              var OUT_START = IN + HOLD;

              function fireSfx(id, t) {
                root.dispatchEvent(
                  new CustomEvent("hf:sfx", { detail: { id: id, t: t }, bubbles: true }),
                );
              }

              // Explicit both-endpoints state makes tl.seek(0) deterministic.
              // --cs-split is the only owner of both clip and divider progress.
              gsap.set(stage, { opacity: 0, "--cs-split": 0 });

              var tl = gsap.timeline({ paused: true });

              // IN: stage settle, then one shared wipe value travels to split.
              tl.to(stage, { opacity: 1, duration: STAGE_IN, ease: "power2.out" }, 0);
              tl.to(
                stage,
                { "--cs-split": splitPct, duration: WIPE_DURATION, ease: "sine.inOut" },
                WIPE_AT,
              );
              tl.call(
                function () {
                  fireSfx("wipe-land-soft", WIPE_END);
                },
                [],
                WIPE_END,
              );

              // HOLD: deliberately steady at the target split.

              // OUT: release fade.
              tl.to(stage, { opacity: 0, duration: OUT, ease: "power2.out" }, OUT_START);

              tl.seek(0);

              window.__timelines = window.__timelines || {};
              window.__timelines[compositionId] = tl;
            })();
          </script>
        </div>
      </template>
    </body>
  </html>
  ```
</VariablesExplorer>

## Install

<InstallCommand command="npx hyperframes add comparison-split" item="comparison-split" />

That writes one file: `compositions/components/comparison-split.html`.

## Paste it into your composition

Open `compositions/components/comparison-split.html` and copy what is inside into your own composition.

A component has no size or duration of its own. It takes both from the composition
you paste it into.

## Variables

Every one of these has a default, so the piece works untouched. Set the ones you
want to change on the element:

| Variable      | Default      | Accepts                  | What it does                                       |
| ------------- | ------------ | ------------------------ | -------------------------------------------------- |
| `split`       | `50`         | 0% to 100%, step 1%      | Target resting position of the comparison divider. |
| `orientation` | `horizontal` | `horizontal`, `vertical` | Axis and direction used by the comparison wipe.    |
| `labelA`      | `Before`     | string                   | Caption shown on the base before panel.            |
| `labelB`      | `After`      | string                   | Caption shown on the revealed after panel.         |

Set them with `data-variable-values` on the element that mounts it. These are the
defaults, so this behaves exactly like the preview above until you change one:

```html wrap theme={null}
<div
  data-composition-id="comparison-split"
  data-composition-src="compositions/components/comparison-split.html"
  data-variable-values='{"split":50,"orientation":"horizontal","labelA":"Before","labelB":"After"}'
></div>
```

## Source

<Accordion title={`comparison-split.html`}>
  ```html theme={null}
  <!doctype html>
  <!--
    comparison-split: HyperFrames video primitive (ui-props / holdable / compare)

    Concept: two full-bleed treatments share one frame. The muted before panel
    stays fully visible as the base, while the vivid after panel wipes over it
    from the leading edge. A persistent divider marks the shared clip boundary.
    One mechanic, one job: compare two visual states.

    Compiled-from evidence: fixture + blueprint (re-filed from prove), from the
    video-primitives compare shelf.

    Use when: a scene needs a direct before-and-after comparison, a redesign
    reveal, or a visual treatment contrast that must remain readable during a
    long hold.

    Variables (declared in data-composition-variables below):
      - split (number, default 50, range 0 to 100%): target resting position.
      - orientation (horizontal | vertical, default horizontal): horizontal uses
        a vertical divider traveling left to right, vertical uses a horizontal
        divider traveling top to bottom.
      - labelA (string, default "Before"): caption on the base panel.
      - labelB (string, default "After"): caption on the revealed panel.

    Envelope (fixed IN/OUT, elastic HOLD only, never gsap.timeScale()):
      IN_BASE  = 1.40s  stage settles, then the divider wipes from 0% to split
      HOLD     = elastic = max(0, D - (IN_BASE + OUT_BASE)); deliberately still
                 so the target comparison remains easy to inspect
      OUT_BASE = 0.50s  release fade
      If D < IN_BASE + OUT_BASE, IN and OUT scale down together so IN + OUT == D
      and HOLD == 0.

    Sync point: wipe-land is fixed at WIPE_END_BASE = 1.30s inside IN. It scales
    proportionally only when the full envelope is shorter than 1.90s, and never
    moves into elastic HOLD.

    Sound cue: a soft wipe landing hook fires at wipe-land. This primitive never
    plays audio. It dispatches a bubbling `hf:sfx` CustomEvent with id
    "wipe-land-soft", so scene-level audio mixing owns playback.

    Mount contract: this file is a MOUNTABLE SUB-COMPOSITION. A host loads it via
    data-composition-src, and the runtime clones only <template> contents. All
    live styles, markup, GSAP, and timeline registration therefore live inside
    <template>. #root is styled by id, fills the host with inset:0, establishes
    the cqw/cqh container, and has no data-width or data-height. The composition
    id is the hardcoded literal "comparison-split" because mount flattening
    strips data-composition-id from the live root. Variables come from
    window.__hyperframes.getVariables(), which merges declared defaults with
    per-instance host overrides.
  -->
  <html
    lang="en"
    data-composition-variables='[
      { "id": "split", "type": "number", "role": "layout", "label": "Split position", "description": "Target resting position of the comparison divider.", "default": 50, "min": 0, "max": 100, "step": 1, "unit": "%" },
      { "id": "orientation", "type": "enum", "role": "layout", "label": "Orientation", "description": "Axis and direction used by the comparison wipe.", "default": "horizontal", "options": [{ "value": "horizontal", "label": "Horizontal" }, { "value": "vertical", "label": "Vertical" }] },
      { "id": "labelA", "type": "string", "role": "content", "label": "Before label", "description": "Caption shown on the base before panel.", "default": "Before" },
      { "id": "labelB", "type": "string", "role": "content", "label": "After label", "description": "Caption shown on the revealed after panel.", "default": "After" }
    ]'
  >
    <head>
      <!-- The mount runtime reads variables from <html>, then discards everything
           outside <template>, including this head. -->
    </head>
    <body>
      <template>
        <div id="root" data-composition-id="comparison-split" data-duration="4" data-fps="30">
          <style>
            *,
            *::before,
            *::after {
              box-sizing: border-box;
            }

            /* Root fills the host-owned box. Every internal measurement uses
               cqw/cqh, and every painted color comes from a theme token. */
            #root {
              position: absolute;
              inset: 0;
              container-type: size;
              isolation: isolate;
              overflow: hidden;
              background: var(--bg, #07111f);
              color: var(--fg, #f8fafc);
              font-family: var(--font-body, Inter, system-ui, sans-serif);
            }

            .cs-clip,
            .cs-stage,
            .cs-panel {
              position: absolute;
              inset: 0;
              width: 100%;
              height: 100%;
            }

            .cs-clip {
              overflow: hidden;
            }

            .cs-stage {
              --cs-split: 0;
              opacity: 0;
            }

            .cs-before {
              background:
                linear-gradient(
                    color-mix(in srgb, var(--border, #334155) 38%, transparent) 0.12cqw,
                    transparent 0.12cqw
                  )
                  0 0 / 5cqw 5cqw,
                linear-gradient(
                    90deg,
                    color-mix(in srgb, var(--border, #334155) 38%, transparent) 0.12cqw,
                    transparent 0.12cqw
                  )
                  0 0 / 5cqw 5cqw,
                var(--surface, #172033);
            }

            .cs-after {
              z-index: 2;
              clip-path: inset(0 calc((100 - var(--cs-split)) * 1%) 0 0);
              background: color-mix(in srgb, var(--fg, #f8fafc) 18%, var(--surface, #172033));
            }

            .cs-window {
              position: absolute;
              left: 14cqw;
              top: 18cqh;
              width: 72cqw;
              height: 64cqh;
              overflow: hidden;
              border-radius: min(3cqw, 5cqh);
              border: 0.16cqw solid var(--border, #334155);
              background: color-mix(in srgb, var(--surface, #172033) 90%, var(--muted, #94a3b8));
              box-shadow: 0 2.2cqh 6cqw color-mix(in srgb, var(--bg, #07111f) 50%, transparent);
            }

            .cs-after .cs-window {
              border-color: color-mix(in srgb, var(--fg, #f8fafc) 45%, transparent);
              background: color-mix(in srgb, var(--fg, #f8fafc) 8%, var(--surface, #172033));
              box-shadow: 0 2.2cqh 7cqw rgba(0, 0, 0, 0.18);
            }

            .cs-toolbar {
              display: flex;
              align-items: center;
              gap: var(--space-1, 1.2cqw);
              height: 12cqh;
              padding: 0 var(--space-2, 2.4cqw);
              border-bottom: 0.14cqw solid var(--border, #334155);
            }

            .cs-dot {
              width: min(2.2cqw, 3.2cqh);
              aspect-ratio: 1;
              border-radius: 50%;
              background: var(--muted, #94a3b8);
              opacity: 0.55;
            }

            .cs-after .cs-dot {
              background: var(--accent, #f8fafc);
              opacity: 1;
            }

            .cs-content {
              position: relative;
              height: 52cqh;
            }

            .cs-copy {
              position: absolute;
              left: 7cqw;
              top: 9cqh;
              width: 31cqw;
            }

            .cs-line {
              height: 2.3cqh;
              margin-bottom: var(--space-2, 2.4cqh);
              border-radius: 2cqh;
              background: var(--muted, #94a3b8);
              opacity: 0.48;
            }

            .cs-line:nth-child(1) {
              width: 94%;
            }

            .cs-line:nth-child(2) {
              width: 72%;
            }

            .cs-line:nth-child(3) {
              width: 48%;
            }

            .cs-after .cs-line {
              background: color-mix(in srgb, var(--fg, #f8fafc) 72%, transparent);
              opacity: 1;
            }

            .cs-visual {
              position: absolute;
              right: 7cqw;
              top: 7cqh;
              width: min(22cqw, 32cqh);
              aspect-ratio: 1;
              border-radius: 36% 64% 58% 42%;
              border: 0.3cqw solid var(--border, #334155);
              background: var(--muted, #94a3b8);
              opacity: 0.5;
            }

            .cs-after .cs-visual {
              border-color: color-mix(in srgb, var(--fg, #f8fafc) 45%, transparent);
              background: color-mix(in srgb, var(--fg, #f8fafc) 72%, transparent);
              box-shadow: 0 0 5cqw rgba(0, 0, 0, 0.18);
              opacity: 1;
            }

            .cs-label {
              position: absolute;
              z-index: 4;
              top: var(--space-3, 4cqh);
              padding: var(--space-1, 1.2cqh) var(--space-2, 2.2cqw);
              border: 0.14cqw solid var(--border, #334155);
              border-radius: 999cqw;
              background: var(--surface, #172033);
              color: var(--fg, #f8fafc);
              font-family: var(--font-display, Inter, system-ui, sans-serif);
              font-size: min(3cqw, 4.2cqh);
              font-weight: 700;
              letter-spacing: 0.08em;
              line-height: 1;
              text-transform: uppercase;
              white-space: nowrap;
            }

            .cs-before .cs-label {
              right: var(--space-3, 4cqw);
              color: var(--muted, #94a3b8);
            }

            .cs-after .cs-label {
              left: var(--space-3, 4cqw);
              border-color: color-mix(in srgb, var(--fg, #f8fafc) 45%, transparent);
              background: color-mix(in srgb, var(--fg, #f8fafc) 8%, var(--surface, #172033));
            }

            .cs-divider {
              position: absolute;
              z-index: 5;
              top: 0;
              bottom: 0;
              left: calc(var(--cs-split) * 1%);
              width: 0.45cqw;
              transform: translateX(-50%);
              background: var(--fg, #f8fafc);
              box-shadow:
                0 0 1.4cqw color-mix(in srgb, var(--fg, #f8fafc) 45%, transparent),
                0 0 3cqw rgba(0, 0, 0, 0.45);
              pointer-events: none;
            }

            .cs-divider::after {
              content: "";
              position: absolute;
              left: 50%;
              top: 50%;
              width: min(5cqw, 7cqh);
              aspect-ratio: 1;
              transform: translate(-50%, -50%);
              border: 0.3cqw solid var(--bg, #07111f);
              border-radius: 50%;
              background: var(--fg, #f8fafc);
              box-shadow: 0 0 2.2cqw color-mix(in srgb, var(--fg, #f8fafc) 45%, transparent);
            }

            /* INVARIANT: vertical changes only the axis mapping. The after clip
               and divider still read the same --cs-split value. */
            #root[data-orientation="vertical"] .cs-after {
              clip-path: inset(0 0 calc((100 - var(--cs-split)) * 1%) 0);
            }

            #root[data-orientation="vertical"] .cs-before .cs-label {
              top: auto;
              right: var(--space-3, 4cqw);
              bottom: var(--space-3, 4cqh);
            }

            #root[data-orientation="vertical"] .cs-divider {
              top: calc(var(--cs-split) * 1%);
              right: 0;
              bottom: auto;
              left: 0;
              width: 100%;
              height: 0.45cqh;
              transform: translateY(-50%);
            }
          </style>

          <div
            id="comparison-split-clip"
            class="cs-clip clip"
            data-start="0"
            data-duration="4"
            data-track-index="0"
          >
            <div class="cs-stage">
              <section class="cs-panel cs-before" aria-label="Before panel">
                <div class="cs-label"></div>
                <div class="cs-window">
                  <div class="cs-toolbar">
                    <span class="cs-dot"></span>
                    <span class="cs-dot"></span>
                    <span class="cs-dot"></span>
                  </div>
                  <div class="cs-content">
                    <div class="cs-copy">
                      <div class="cs-line"></div>
                      <div class="cs-line"></div>
                      <div class="cs-line"></div>
                    </div>
                    <div class="cs-visual"></div>
                  </div>
                </div>
              </section>

              <section class="cs-panel cs-after" aria-label="After panel">
                <div class="cs-label"></div>
                <div class="cs-window">
                  <div class="cs-toolbar">
                    <span class="cs-dot"></span>
                    <span class="cs-dot"></span>
                    <span class="cs-dot"></span>
                  </div>
                  <div class="cs-content">
                    <div class="cs-copy">
                      <div class="cs-line"></div>
                      <div class="cs-line"></div>
                      <div class="cs-line"></div>
                    </div>
                    <div class="cs-visual"></div>
                  </div>
                </div>
              </section>

              <div class="cs-divider" aria-hidden="true"></div>
            </div>
          </div>

          <script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
          <script>
            (function () {
              "use strict";

              var root = document.getElementById("root");
              // Hardcoded because mount flattening strips data-composition-id
              // from the live root before this timeline registers.
              var compositionId = "comparison-split";
              var stage = root.querySelector(".cs-stage");
              var labelAEl = root.querySelector(".cs-before .cs-label");
              var labelBEl = root.querySelector(".cs-after .cs-label");

              // EDIT ZONE: declarations above and registry metadata change
              // together. This API owns defaults plus per-instance overrides.
              var vars =
                window.__hyperframes && window.__hyperframes.getVariables
                  ? window.__hyperframes.getVariables()
                  : {};

              var rawSplit = vars.split == null ? 50 : Number(vars.split);
              // INVARIANT: split always clamps into the declared 0 to 100 range.
              var splitPct = Number.isFinite(rawSplit) ? Math.max(0, Math.min(100, rawSplit)) : 50;
              // INVARIANT: only horizontal or vertical reaches the renderer.
              var orientation = vars.orientation === "vertical" ? "vertical" : "horizontal";
              var labelAText = vars.labelA == null ? "" : String(vars.labelA);
              var labelBText = vars.labelB == null ? "" : String(vars.labelB);

              root.setAttribute("data-orientation", orientation);
              labelAEl.textContent = labelAText;
              labelBEl.textContent = labelBText;

              // RETIME RANGE: fixed IN and OUT scale together only when D is too
              // short. HOLD is the sole elastic phase. Never use timeScale().
              var IN_BASE = 1.4;
              var OUT_BASE = 0.5;
              var STAGE_IN_BASE = 0.32;
              var WIPE_AT_BASE = 0.25;
              var WIPE_DURATION_BASE = 1.05;
              var WIPE_END_BASE = WIPE_AT_BASE + WIPE_DURATION_BASE;

              var duration = Math.max(0.001, parseFloat(root.dataset.duration || "4"));
              var totalBase = IN_BASE + OUT_BASE;
              var scale = duration < totalBase ? duration / totalBase : 1;
              var IN = IN_BASE * scale;
              var OUT = OUT_BASE * scale;
              var STAGE_IN = STAGE_IN_BASE * scale;
              var WIPE_AT = WIPE_AT_BASE * scale;
              var WIPE_DURATION = WIPE_DURATION_BASE * scale;
              var WIPE_END = WIPE_END_BASE * scale;
              var HOLD = Math.max(0, duration - (IN + OUT));
              var OUT_START = IN + HOLD;

              function fireSfx(id, t) {
                root.dispatchEvent(
                  new CustomEvent("hf:sfx", { detail: { id: id, t: t }, bubbles: true }),
                );
              }

              // Explicit both-endpoints state makes tl.seek(0) deterministic.
              // --cs-split is the only owner of both clip and divider progress.
              gsap.set(stage, { opacity: 0, "--cs-split": 0 });

              var tl = gsap.timeline({ paused: true });

              // IN: stage settle, then one shared wipe value travels to split.
              tl.to(stage, { opacity: 1, duration: STAGE_IN, ease: "power2.out" }, 0);
              tl.to(
                stage,
                { "--cs-split": splitPct, duration: WIPE_DURATION, ease: "sine.inOut" },
                WIPE_AT,
              );
              tl.call(
                function () {
                  fireSfx("wipe-land-soft", WIPE_END);
                },
                [],
                WIPE_END,
              );

              // HOLD: deliberately steady at the target split.

              // OUT: release fade.
              tl.to(stage, { opacity: 0, duration: OUT, ease: "power2.out" }, OUT_START);

              tl.seek(0);

              window.__timelines = window.__timelines || {};
              window.__timelines[compositionId] = tl;
            })();
          </script>
        </div>
      </template>
    </body>
  </html>
  ```
</Accordion>

Tagged `prop` `ui-props` `compare` `holdable` `before-after` `wipe`.

## Related topics

* [Browse the complete Catalog](/catalog)
* [Add assets and Catalog items in Studio](/studio/assets-and-blocks)
* [Build a richer composition](/go-further)