> ## 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.

# Neon Border

> Two arcs of light travel the edge of a rounded panel and snap corner to corner, trailing a soft three-layer bloom. A lower third for a name and role.

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/blocks/lt-neon-border.json" compositionId="lt-neon-border" compositionSrc="compositions/lt-neon-border.html" variables={[{"id":"name","type":"string","label":"Name","default":"Dr. Maya Chen"},{"id":"role","type":"string","label":"Role","default":"Host · Neuroscientist"},{"id":"accent","type":"color","label":"Accent","default":"#cc9149"},{"id":"movement","type":"enum","label":"Movement","default":"step","options":[{"value":"step","label":"Step (snap at corners)"},{"value":"glide","label":"Glide (smooth)"}]},{"id":"speed","type":"number","label":"Speed","default":1.6,"min":0.2,"max":6,"step":0.1,"unit":"corners/s"},{"id":"cornerRadius","type":"number","label":"Corner radius","default":26,"min":0,"max":90,"step":1,"unit":"px"},{"id":"thickness","type":"number","label":"Thickness","default":5,"min":1,"max":16,"step":1,"unit":"px"},{"id":"arcLength","type":"number","label":"Arc length","default":22,"min":5,"max":100,"step":1,"unit":"%"},{"id":"glow","type":"number","label":"Glow","default":1,"min":0,"max":2,"step":0.05,"unit":"x"}]}>
  ```html lt-neon-border.html theme={null}
  <!doctype html>
  <html lang="en">
    <head>
      <meta charset="UTF-8" />
      <script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
      <style>
        * {
          margin: 0;
          padding: 0;
          box-sizing: border-box;
        }
        html,
        body {
          background: transparent;
          overflow: hidden;
        }
        body {
          width: 1920px;
          height: 1080px;
          font-family: "Inter", sans-serif;
        }

        #root .nb-wrap {
          position: absolute;
          left: 50px;
          bottom: 56px;
          width: 1120px;
          height: 510px;
        }
        #root .nb-svg {
          position: absolute;
          inset: 0;
          display: block;
        }
        /* The frame's inner box, inset by the bloom padding so the copy lands
           inside the traced rectangle. */
        #root .nb-panel {
          position: absolute;
          left: 150px;
          top: 150px;
          width: 820px;
          height: 210px;
          display: flex;
          flex-direction: column;
          justify-content: center;
          gap: 14px;
          padding: 0 52px;
        }
        #root .nb-name {
          display: block;
          font-size: 54px;
          font-weight: 700;
          color: #ffffff;
          line-height: 1;
          letter-spacing: -0.015em;
          white-space: nowrap;
          text-shadow: 0 2px 20px rgba(0, 0, 0, 0.75);
        }
        #root .nb-role {
          display: block;
          font-size: 25px;
          font-weight: 400;
          color: #d5dae3;
          line-height: 1.2;
          letter-spacing: 0.06em;
          text-transform: uppercase;
          white-space: nowrap;
          text-shadow: 0 2px 16px rgba(0, 0, 0, 0.75);
        }
      </style>
    </head>
    <body>
      <div
        id="root"
        data-composition-id="lt-neon-border"
        data-composition-variables='[
          {"id":"name","type":"string","label":"Name","default":"Dr. Maya Chen"},
          {"id":"role","type":"string","label":"Role","default":"Host · Neuroscientist"},
          {"id":"accent","type":"color","label":"Accent","default":"#cc9149"},
          {"id":"movement","type":"enum","label":"Movement","default":"step","options":[{"value":"step","label":"Step (snap at corners)"},{"value":"glide","label":"Glide (smooth)"}]},
          {"id":"speed","type":"number","label":"Speed","default":1.6,"min":0.2,"max":6,"step":0.1,"unit":"corners/s"},
          {"id":"cornerRadius","type":"number","label":"Corner radius","default":26,"min":0,"max":90,"step":1,"unit":"px"},
          {"id":"thickness","type":"number","label":"Thickness","default":5,"min":1,"max":16,"step":1,"unit":"px"},
          {"id":"arcLength","type":"number","label":"Arc length","default":22,"min":5,"max":100,"step":1,"unit":"%"},
          {"id":"glow","type":"number","label":"Glow","default":1,"min":0,"max":2,"step":0.05,"unit":"x"}
        ]'
        data-start="0"
        data-duration="4.8"
        data-width="1920"
        data-height="1080"
      >
        <div id="nb-clip" class="clip" data-start="0" data-duration="4.8" data-track-index="0">
          <div id="nb-wrap" class="nb-wrap">
            <svg
              id="nb-svg"
              class="nb-svg"
              width="1120"
              height="510"
              viewBox="0 0 1120 510"
              fill="none"
              aria-hidden="true"
            >
              <defs>
                <g id="nb-seg-a-glow"></g>
                <g id="nb-seg-a-core"></g>
                <g id="nb-seg-b-glow"></g>
                <g id="nb-seg-b-core"></g>
              </defs>
              <g transform="translate(150,150)">
                <!-- Wide bloom sits UNDER the panel so the halo reads outside the
                     frame and the interior stays hardware-clean. -->
                <g id="nb-bloom-under"></g>
                <path id="nb-fill" d="" fill="rgba(9,11,15,0.78)" />
                <path id="nb-rail" d="" fill="none" stroke-linejoin="round" />
                <g id="nb-bloom-over"></g>
              </g>
            </svg>
            <div id="nb-panel" class="nb-panel">
              <span id="nb-name" class="nb-name" data-var-text="name">Dr. Maya Chen</span>
              <span id="nb-role" class="nb-role" data-var-text="role">Host · Neuroscientist</span>
            </div>
          </div>
        </div>
      </div>

      <script>
        (function () {
          window.__timelines = window.__timelines || {};

          var SVG_NS = "http://www.w3.org/2000/svg";
          var W = 820; // traced rectangle width
          var H = 210; // traced rectangle height
          var DUR = 4.8;

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

          function num(v, fallback) {
            var n = typeof v === "number" ? v : parseFloat(v);
            return isFinite(n) ? n : fallback;
          }

          var accent = /^#[0-9a-fA-F]{6}$/.test(String(vars.accent))
            ? String(vars.accent)
            : "#cc9149";
          var mode = vars.movement === "glide" ? "glide" : "step";
          var speed = Math.max(0.05, num(vars.speed, 1.6)); // corners per second
          var radius = Math.min(Math.min(W, H) / 2, Math.max(0, num(vars.cornerRadius, 26)));
          var thickness = Math.max(0.5, num(vars.thickness, 5));
          var arcFrac = Math.min(1, Math.max(0.02, num(vars.arcLength, 22) / 100));
          var glow = Math.max(0, num(vars.glow, 1));

          // Hot core: the accent lifted most of the way to white, the way a real
          // filament reads brighter than its halo.
          function towardWhite(hex, amount) {
            var v = parseInt(hex.slice(1), 16);
            var out = "#";
            for (var s = 16; s >= 0; s -= 8) {
              var c = (v >> s) & 255;
              var m = Math.round(c + (255 - c) * amount);
              out += (m < 16 ? "0" : "") + m.toString(16);
            }
            return out;
          }
          var hot = towardWhite(accent, 0.78);

          // ---- geometry -------------------------------------------------------
          // Rounded rect, clockwise, starting where the top edge leaves the
          // top-left corner arc.
          var r = radius;
          var arc = "A " + r + " " + r + " 0 0 1 ";
          var d = [
            "M " + r + " 0",
            "H " + (W - r),
            arc + W + " " + r,
            "V " + (H - r),
            arc + (W - r) + " " + H,
            "H " + r,
            arc + "0 " + (H - r),
            "V " + r,
            arc + r + " 0",
            "Z",
          ].join(" ");

          var fillEl = document.getElementById("nb-fill");
          var railEl = document.getElementById("nb-rail");
          fillEl.setAttribute("d", d);
          railEl.setAttribute("d", d);
          railEl.setAttribute("stroke", accent);
          railEl.setAttribute("stroke-width", String(thickness));
          railEl.setAttribute("stroke-opacity", "0.14");

          // Analytic perimeter, then rescaled to whatever length the renderer
          // actually measures for the path so dash distances line up exactly.
          var SW = W - 2 * r; // straight run, horizontal
          var SH = H - 2 * r; // straight run, vertical
          var AC = (Math.PI * r) / 2; // one corner arc
          var P_ANALYTIC = 2 * SW + 2 * SH + 4 * AC;
          var P = railEl.getTotalLength() || P_ANALYTIC;
          var K = P / P_ANALYTIC;

          // Distance along the path of the MIDPOINT of each corner arc, so the
          // light parks centred on the corner rather than skidding past it.
          var CORNERS = [
            (SW + AC / 2) * K, // top-right
            (SW + SH + 1.5 * AC) * K, // bottom-right
            (2 * SW + SH + 2.5 * AC) * K, // bottom-left
            (2 * SW + 2 * SH + 3.5 * AC) * K, // top-left
          ];

          /** Absolute path distance of corner k, for any integer k (k may be
           * negative or beyond one lap). Pure function of k — no accumulator. */
          function cornerPos(k) {
            var lap = Math.floor(k / 4);
            var i = k - lap * 4;
            return CORNERS[i] + lap * P;
          }

          // ---- easing ---------------------------------------------------------
          // The step curve overshoots (y2 = 1.05); that overshoot IS the snap.
          function cubicBezier(x1, y1, x2, y2) {
            function axis(t, a, b) {
              var u = 1 - t;
              return 3 * u * u * t * a + 3 * u * t * t * b + t * t * t;
            }
            return function (x) {
              if (x <= 0) return 0;
              if (x >= 1) return 1;
              var lo = 0;
              var hi = 1;
              var t = x;
              // Fixed iteration count: same input, same output, every run.
              for (var i = 0; i < 32; i++) {
                t = (lo + hi) / 2;
                if (axis(t, x1, x2) < x) lo = t;
                else hi = t;
              }
              return axis(t, y1, y2);
            };
          }
          var ease =
            mode === "glide" ? cubicBezier(0.65, 0, 0.35, 1) : cubicBezier(0.72, 0.16, 0.18, 1.05);

          var beat = 1 / speed; // seconds per corner hop

          /** Head position (path distance) at time t. floor/frac of t/beat is the
           * closed form of the reference's `stepT += dt` accumulator. */
          function headAt(t) {
            var total = t / beat;
            var k = Math.floor(total);
            var u = total - k;
            var a = cornerPos(k);
            var b = cornerPos(k + 1);
            return a + (b - a) * ease(u);
          }

          // ---- arc construction ----------------------------------------------
          // Each arc is a run of abutting dash segments whose opacity falls off
          // behind the head; that ramp is the taper. Geometry lives once in
          // <defs> and is shared by every bloom layer through <use>.
          function buildSegments(groupId, count, falloff) {
            var g = document.getElementById(groupId);
            var segs = [];
            for (var i = 0; i < count; i++) {
              var p = document.createElementNS(SVG_NS, "path");
              p.setAttribute("d", d);
              p.setAttribute("fill", "none");
              p.setAttribute("stroke-linecap", i === 0 ? "round" : "butt");
              p.setAttribute("opacity", String(Math.pow(1 - i / count, falloff)));
              g.appendChild(p);
              segs.push(p);
            }
            return segs;
          }

          var GLOW_SEGS = 20;
          var CORE_SEGS = 26;
          var glowLen = arcFrac * P;
          var coreLen = 0.34 * glowLen;

          var arcs = [
            {
              offset: 0,
              glow: buildSegments("nb-seg-a-glow", GLOW_SEGS, 2.6),
              core: buildSegments("nb-seg-a-core", CORE_SEGS, 1.4),
            },
            {
              // Half a lap behind: the diametrically opposite corner. The pairing
              // is most of why the effect reads as designed rather than random.
              offset: 2,
              glow: buildSegments("nb-seg-b-glow", GLOW_SEGS, 2.6),
              core: buildSegments("nb-seg-b-core", CORE_SEGS, 1.4),
            },
          ];

          // Three stacked bloom layers (soft / medium / wide) plus the filament.
          // `spread` widens the stroke before it is blurred — that pairing, not
          // the blur alone, is what makes the halo read as emitted light.
          var MAX_REACH = 36;
          var LAYERS = [
            { blur: 30, spread: 1, opacity: 0.18, stroke: accent, deep: true },
            { blur: 15, spread: 0.6, opacity: 0.3, stroke: accent, deep: true },
            { blur: 8, spread: 0.3, opacity: 0.5, stroke: accent, deep: true },
            { blur: 4, spread: 0.05, opacity: 0.9, stroke: hot, core: true },
            { blur: 0, spread: -0.012, opacity: 1, stroke: "#ffffff", core: true },
          ];

          var under = document.getElementById("nb-bloom-under");
          var over = document.getElementById("nb-bloom-over");
          ["a", "b"].forEach(function (tag) {
            LAYERS.forEach(function (layer) {
              var u = document.createElementNS(SVG_NS, "use");
              u.setAttribute("href", "#nb-seg-" + tag + "-" + (layer.core ? "core" : "glow"));
              u.setAttribute("stroke", layer.stroke);
              u.setAttribute(
                "stroke-width",
                String(Math.max(0.5, thickness + 2 * layer.spread * MAX_REACH * glow)),
              );
              u.setAttribute("opacity", String(Math.min(1, layer.opacity * glow)));
              if (layer.blur > 0) u.style.filter = "blur(" + layer.blur + "px)";
              (layer.deep ? under : over).appendChild(u);
            });
          });

          /** Lay a segment run out behind `head`. Every value derives from head. */
          function layout(segs, head, length) {
            var step = length / segs.length;
            for (var i = 0; i < segs.length; i++) {
              var start = head - (i + 1) * step;
              start = ((start % P) + P) % P;
              segs[i].setAttribute("stroke-dasharray", step + " " + (P - step));
              segs[i].setAttribute("stroke-dashoffset", String(-start));
            }
          }

          function render(t) {
            for (var i = 0; i < arcs.length; i++) {
              var head = headAt(t + arcs[i].offset * beat);
              layout(arcs[i].glow, head, glowLen);
              layout(arcs[i].core, head, coreLen);
            }
          }

          // ---- timeline -------------------------------------------------------
          var wrap = document.getElementById("nb-wrap");
          var panel = document.getElementById("nb-panel");
          var nameEl = document.getElementById("nb-name");
          var roleEl = document.getElementById("nb-role");

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

          gsap.set(wrap, { opacity: 0, scale: 0.965, transformOrigin: "0% 100%" });
          gsap.set(nameEl, { y: 18, opacity: 0 });
          gsap.set(roleEl, { y: 12, opacity: 0 });

          // The driver: linear, spans the whole clip, and every arc position is
          // recomputed from its own time value. Seeking to frame N gives the same
          // state as playing to frame N because nothing carries over.
          var driver = { t: 0 };
          tl.to(
            driver,
            {
              t: DUR,
              duration: DUR,
              ease: "none",
              onUpdate: function () {
                render(driver.t);
              },
            },
            0,
          );

          tl.to(wrap, { opacity: 1, scale: 1, duration: 0.55, ease: "power3.out" }, 0.08);
          tl.to(nameEl, { y: 0, opacity: 1, duration: 0.5, ease: "power3.out" }, 0.3);
          tl.to(roleEl, { y: 0, opacity: 1, duration: 0.5, ease: "power3.out" }, 0.44);

          tl.to(roleEl, { y: -10, opacity: 0, duration: 0.3, ease: "power2.in" }, 4.24);
          tl.to(nameEl, { y: -14, opacity: 0, duration: 0.32, ease: "power2.in" }, 4.3);
          tl.to(wrap, { opacity: 0, scale: 0.985, duration: 0.36, ease: "power2.in" }, 4.36);
          tl.set(panel, { visibility: "hidden" }, 4.76);

          render(0);

          window.__timelines["lt-neon-border"] = tl;
        })();
      </script>
    </body>
  </html>
  ```
</VariablesExplorer>

## Install

<InstallCommand command="npx hyperframes add lt-neon-border" item="lt-neon-border" />

That writes one file: `compositions/lt-neon-border.html`.

## Add it to your video

It runs for 4.8 seconds at 1920×1080. Paste this into your composition:

```html index.html theme={null}
<div
  data-composition-id="lt-neon-border"
  data-composition-src="compositions/lt-neon-border.html"
  data-start="0"
  data-duration="4.8"
  data-track-index="1"
  data-width="1920"
  data-height="1080"
></div>
```

Move it in time with `data-start`. Put it on a different timeline row with
`data-track-index`. See [data attributes](/concepts/data-attributes) for the rest.

## Change how it looks

Set these CSS variables on the block:

* `undefined` — Name. Defaults to `Dr. Maya Chen`.
* `undefined` — Role. Defaults to `Host · Neuroscientist`.
* `undefined` — Accent. Defaults to `#cc9149`.
* `undefined` — Movement. Defaults to `step`. Options: `step`, `glide`.
* `undefined` — Speed. Defaults to `1.6`.
* `undefined` — Corner radius. Defaults to `26`.
* `undefined` — Thickness. Defaults to `5`.
* `undefined` — Arc length. Defaults to `22`.
* `undefined` — Glow. Defaults to `1`.

## 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 |
| -------------- | ----------------------- | --------------------------------------------- | ------------ |
| `name`         | `Dr. Maya Chen`         | string                                        |              |
| `role`         | `Host · Neuroscientist` | string                                        |              |
| `accent`       | `#cc9149`               | color                                         |              |
| `movement`     | `step`                  | `step`, `glide`                               |              |
| `speed`        | `1.6`                   | 0.2corners/s to 6corners/s, step 0.1corners/s |              |
| `cornerRadius` | `26`                    | 0px to 90px, step 1px                         |              |
| `thickness`    | `5`                     | 1px to 16px, step 1px                         |              |
| `arcLength`    | `22`                    | 5% to 100%, step 1%                           |              |
| `glow`         | `1`                     | 0x to 2x, step 0.05x                          |              |

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="lt-neon-border"
  data-composition-src="compositions/lt-neon-border.html"
  data-variable-values='{"name":"Dr. Maya Chen","role":"Host · Neuroscientist","accent":"#cc9149","movement":"step","speed":1.6,"cornerRadius":26,"thickness":5,"arcLength":22,"glow":1}'
></div>
```

## Source

<Accordion title={`lt-neon-border.html`}>
  ```html theme={null}
  <!doctype html>
  <html lang="en">
    <head>
      <meta charset="UTF-8" />
      <script src="https://cdn.jsdelivr.net/npm/gsap@3.14.2/dist/gsap.min.js"></script>
      <style>
        * {
          margin: 0;
          padding: 0;
          box-sizing: border-box;
        }
        html,
        body {
          background: transparent;
          overflow: hidden;
        }
        body {
          width: 1920px;
          height: 1080px;
          font-family: "Inter", sans-serif;
        }

        #root .nb-wrap {
          position: absolute;
          left: 50px;
          bottom: 56px;
          width: 1120px;
          height: 510px;
        }
        #root .nb-svg {
          position: absolute;
          inset: 0;
          display: block;
        }
        /* The frame's inner box, inset by the bloom padding so the copy lands
           inside the traced rectangle. */
        #root .nb-panel {
          position: absolute;
          left: 150px;
          top: 150px;
          width: 820px;
          height: 210px;
          display: flex;
          flex-direction: column;
          justify-content: center;
          gap: 14px;
          padding: 0 52px;
        }
        #root .nb-name {
          display: block;
          font-size: 54px;
          font-weight: 700;
          color: #ffffff;
          line-height: 1;
          letter-spacing: -0.015em;
          white-space: nowrap;
          text-shadow: 0 2px 20px rgba(0, 0, 0, 0.75);
        }
        #root .nb-role {
          display: block;
          font-size: 25px;
          font-weight: 400;
          color: #d5dae3;
          line-height: 1.2;
          letter-spacing: 0.06em;
          text-transform: uppercase;
          white-space: nowrap;
          text-shadow: 0 2px 16px rgba(0, 0, 0, 0.75);
        }
      </style>
    </head>
    <body>
      <div
        id="root"
        data-composition-id="lt-neon-border"
        data-composition-variables='[
          {"id":"name","type":"string","label":"Name","default":"Dr. Maya Chen"},
          {"id":"role","type":"string","label":"Role","default":"Host · Neuroscientist"},
          {"id":"accent","type":"color","label":"Accent","default":"#cc9149"},
          {"id":"movement","type":"enum","label":"Movement","default":"step","options":[{"value":"step","label":"Step (snap at corners)"},{"value":"glide","label":"Glide (smooth)"}]},
          {"id":"speed","type":"number","label":"Speed","default":1.6,"min":0.2,"max":6,"step":0.1,"unit":"corners/s"},
          {"id":"cornerRadius","type":"number","label":"Corner radius","default":26,"min":0,"max":90,"step":1,"unit":"px"},
          {"id":"thickness","type":"number","label":"Thickness","default":5,"min":1,"max":16,"step":1,"unit":"px"},
          {"id":"arcLength","type":"number","label":"Arc length","default":22,"min":5,"max":100,"step":1,"unit":"%"},
          {"id":"glow","type":"number","label":"Glow","default":1,"min":0,"max":2,"step":0.05,"unit":"x"}
        ]'
        data-start="0"
        data-duration="4.8"
        data-width="1920"
        data-height="1080"
      >
        <div id="nb-clip" class="clip" data-start="0" data-duration="4.8" data-track-index="0">
          <div id="nb-wrap" class="nb-wrap">
            <svg
              id="nb-svg"
              class="nb-svg"
              width="1120"
              height="510"
              viewBox="0 0 1120 510"
              fill="none"
              aria-hidden="true"
            >
              <defs>
                <g id="nb-seg-a-glow"></g>
                <g id="nb-seg-a-core"></g>
                <g id="nb-seg-b-glow"></g>
                <g id="nb-seg-b-core"></g>
              </defs>
              <g transform="translate(150,150)">
                <!-- Wide bloom sits UNDER the panel so the halo reads outside the
                     frame and the interior stays hardware-clean. -->
                <g id="nb-bloom-under"></g>
                <path id="nb-fill" d="" fill="rgba(9,11,15,0.78)" />
                <path id="nb-rail" d="" fill="none" stroke-linejoin="round" />
                <g id="nb-bloom-over"></g>
              </g>
            </svg>
            <div id="nb-panel" class="nb-panel">
              <span id="nb-name" class="nb-name" data-var-text="name">Dr. Maya Chen</span>
              <span id="nb-role" class="nb-role" data-var-text="role">Host · Neuroscientist</span>
            </div>
          </div>
        </div>
      </div>

      <script>
        (function () {
          window.__timelines = window.__timelines || {};

          var SVG_NS = "http://www.w3.org/2000/svg";
          var W = 820; // traced rectangle width
          var H = 210; // traced rectangle height
          var DUR = 4.8;

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

          function num(v, fallback) {
            var n = typeof v === "number" ? v : parseFloat(v);
            return isFinite(n) ? n : fallback;
          }

          var accent = /^#[0-9a-fA-F]{6}$/.test(String(vars.accent))
            ? String(vars.accent)
            : "#cc9149";
          var mode = vars.movement === "glide" ? "glide" : "step";
          var speed = Math.max(0.05, num(vars.speed, 1.6)); // corners per second
          var radius = Math.min(Math.min(W, H) / 2, Math.max(0, num(vars.cornerRadius, 26)));
          var thickness = Math.max(0.5, num(vars.thickness, 5));
          var arcFrac = Math.min(1, Math.max(0.02, num(vars.arcLength, 22) / 100));
          var glow = Math.max(0, num(vars.glow, 1));

          // Hot core: the accent lifted most of the way to white, the way a real
          // filament reads brighter than its halo.
          function towardWhite(hex, amount) {
            var v = parseInt(hex.slice(1), 16);
            var out = "#";
            for (var s = 16; s >= 0; s -= 8) {
              var c = (v >> s) & 255;
              var m = Math.round(c + (255 - c) * amount);
              out += (m < 16 ? "0" : "") + m.toString(16);
            }
            return out;
          }
          var hot = towardWhite(accent, 0.78);

          // ---- geometry -------------------------------------------------------
          // Rounded rect, clockwise, starting where the top edge leaves the
          // top-left corner arc.
          var r = radius;
          var arc = "A " + r + " " + r + " 0 0 1 ";
          var d = [
            "M " + r + " 0",
            "H " + (W - r),
            arc + W + " " + r,
            "V " + (H - r),
            arc + (W - r) + " " + H,
            "H " + r,
            arc + "0 " + (H - r),
            "V " + r,
            arc + r + " 0",
            "Z",
          ].join(" ");

          var fillEl = document.getElementById("nb-fill");
          var railEl = document.getElementById("nb-rail");
          fillEl.setAttribute("d", d);
          railEl.setAttribute("d", d);
          railEl.setAttribute("stroke", accent);
          railEl.setAttribute("stroke-width", String(thickness));
          railEl.setAttribute("stroke-opacity", "0.14");

          // Analytic perimeter, then rescaled to whatever length the renderer
          // actually measures for the path so dash distances line up exactly.
          var SW = W - 2 * r; // straight run, horizontal
          var SH = H - 2 * r; // straight run, vertical
          var AC = (Math.PI * r) / 2; // one corner arc
          var P_ANALYTIC = 2 * SW + 2 * SH + 4 * AC;
          var P = railEl.getTotalLength() || P_ANALYTIC;
          var K = P / P_ANALYTIC;

          // Distance along the path of the MIDPOINT of each corner arc, so the
          // light parks centred on the corner rather than skidding past it.
          var CORNERS = [
            (SW + AC / 2) * K, // top-right
            (SW + SH + 1.5 * AC) * K, // bottom-right
            (2 * SW + SH + 2.5 * AC) * K, // bottom-left
            (2 * SW + 2 * SH + 3.5 * AC) * K, // top-left
          ];

          /** Absolute path distance of corner k, for any integer k (k may be
           * negative or beyond one lap). Pure function of k — no accumulator. */
          function cornerPos(k) {
            var lap = Math.floor(k / 4);
            var i = k - lap * 4;
            return CORNERS[i] + lap * P;
          }

          // ---- easing ---------------------------------------------------------
          // The step curve overshoots (y2 = 1.05); that overshoot IS the snap.
          function cubicBezier(x1, y1, x2, y2) {
            function axis(t, a, b) {
              var u = 1 - t;
              return 3 * u * u * t * a + 3 * u * t * t * b + t * t * t;
            }
            return function (x) {
              if (x <= 0) return 0;
              if (x >= 1) return 1;
              var lo = 0;
              var hi = 1;
              var t = x;
              // Fixed iteration count: same input, same output, every run.
              for (var i = 0; i < 32; i++) {
                t = (lo + hi) / 2;
                if (axis(t, x1, x2) < x) lo = t;
                else hi = t;
              }
              return axis(t, y1, y2);
            };
          }
          var ease =
            mode === "glide" ? cubicBezier(0.65, 0, 0.35, 1) : cubicBezier(0.72, 0.16, 0.18, 1.05);

          var beat = 1 / speed; // seconds per corner hop

          /** Head position (path distance) at time t. floor/frac of t/beat is the
           * closed form of the reference's `stepT += dt` accumulator. */
          function headAt(t) {
            var total = t / beat;
            var k = Math.floor(total);
            var u = total - k;
            var a = cornerPos(k);
            var b = cornerPos(k + 1);
            return a + (b - a) * ease(u);
          }

          // ---- arc construction ----------------------------------------------
          // Each arc is a run of abutting dash segments whose opacity falls off
          // behind the head; that ramp is the taper. Geometry lives once in
          // <defs> and is shared by every bloom layer through <use>.
          function buildSegments(groupId, count, falloff) {
            var g = document.getElementById(groupId);
            var segs = [];
            for (var i = 0; i < count; i++) {
              var p = document.createElementNS(SVG_NS, "path");
              p.setAttribute("d", d);
              p.setAttribute("fill", "none");
              p.setAttribute("stroke-linecap", i === 0 ? "round" : "butt");
              p.setAttribute("opacity", String(Math.pow(1 - i / count, falloff)));
              g.appendChild(p);
              segs.push(p);
            }
            return segs;
          }

          var GLOW_SEGS = 20;
          var CORE_SEGS = 26;
          var glowLen = arcFrac * P;
          var coreLen = 0.34 * glowLen;

          var arcs = [
            {
              offset: 0,
              glow: buildSegments("nb-seg-a-glow", GLOW_SEGS, 2.6),
              core: buildSegments("nb-seg-a-core", CORE_SEGS, 1.4),
            },
            {
              // Half a lap behind: the diametrically opposite corner. The pairing
              // is most of why the effect reads as designed rather than random.
              offset: 2,
              glow: buildSegments("nb-seg-b-glow", GLOW_SEGS, 2.6),
              core: buildSegments("nb-seg-b-core", CORE_SEGS, 1.4),
            },
          ];

          // Three stacked bloom layers (soft / medium / wide) plus the filament.
          // `spread` widens the stroke before it is blurred — that pairing, not
          // the blur alone, is what makes the halo read as emitted light.
          var MAX_REACH = 36;
          var LAYERS = [
            { blur: 30, spread: 1, opacity: 0.18, stroke: accent, deep: true },
            { blur: 15, spread: 0.6, opacity: 0.3, stroke: accent, deep: true },
            { blur: 8, spread: 0.3, opacity: 0.5, stroke: accent, deep: true },
            { blur: 4, spread: 0.05, opacity: 0.9, stroke: hot, core: true },
            { blur: 0, spread: -0.012, opacity: 1, stroke: "#ffffff", core: true },
          ];

          var under = document.getElementById("nb-bloom-under");
          var over = document.getElementById("nb-bloom-over");
          ["a", "b"].forEach(function (tag) {
            LAYERS.forEach(function (layer) {
              var u = document.createElementNS(SVG_NS, "use");
              u.setAttribute("href", "#nb-seg-" + tag + "-" + (layer.core ? "core" : "glow"));
              u.setAttribute("stroke", layer.stroke);
              u.setAttribute(
                "stroke-width",
                String(Math.max(0.5, thickness + 2 * layer.spread * MAX_REACH * glow)),
              );
              u.setAttribute("opacity", String(Math.min(1, layer.opacity * glow)));
              if (layer.blur > 0) u.style.filter = "blur(" + layer.blur + "px)";
              (layer.deep ? under : over).appendChild(u);
            });
          });

          /** Lay a segment run out behind `head`. Every value derives from head. */
          function layout(segs, head, length) {
            var step = length / segs.length;
            for (var i = 0; i < segs.length; i++) {
              var start = head - (i + 1) * step;
              start = ((start % P) + P) % P;
              segs[i].setAttribute("stroke-dasharray", step + " " + (P - step));
              segs[i].setAttribute("stroke-dashoffset", String(-start));
            }
          }

          function render(t) {
            for (var i = 0; i < arcs.length; i++) {
              var head = headAt(t + arcs[i].offset * beat);
              layout(arcs[i].glow, head, glowLen);
              layout(arcs[i].core, head, coreLen);
            }
          }

          // ---- timeline -------------------------------------------------------
          var wrap = document.getElementById("nb-wrap");
          var panel = document.getElementById("nb-panel");
          var nameEl = document.getElementById("nb-name");
          var roleEl = document.getElementById("nb-role");

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

          gsap.set(wrap, { opacity: 0, scale: 0.965, transformOrigin: "0% 100%" });
          gsap.set(nameEl, { y: 18, opacity: 0 });
          gsap.set(roleEl, { y: 12, opacity: 0 });

          // The driver: linear, spans the whole clip, and every arc position is
          // recomputed from its own time value. Seeking to frame N gives the same
          // state as playing to frame N because nothing carries over.
          var driver = { t: 0 };
          tl.to(
            driver,
            {
              t: DUR,
              duration: DUR,
              ease: "none",
              onUpdate: function () {
                render(driver.t);
              },
            },
            0,
          );

          tl.to(wrap, { opacity: 1, scale: 1, duration: 0.55, ease: "power3.out" }, 0.08);
          tl.to(nameEl, { y: 0, opacity: 1, duration: 0.5, ease: "power3.out" }, 0.3);
          tl.to(roleEl, { y: 0, opacity: 1, duration: 0.5, ease: "power3.out" }, 0.44);

          tl.to(roleEl, { y: -10, opacity: 0, duration: 0.3, ease: "power2.in" }, 4.24);
          tl.to(nameEl, { y: -14, opacity: 0, duration: 0.32, ease: "power2.in" }, 4.3);
          tl.to(wrap, { opacity: 0, scale: 0.985, duration: 0.36, ease: "power2.in" }, 4.36);
          tl.set(panel, { visibility: "hidden" }, 4.76);

          render(0);

          window.__timelines["lt-neon-border"] = tl;
        })();
      </script>
    </body>
  </html>
  ```
</Accordion>

Tagged `lower-third` `glow` `loop` `video-primitive`.

## Related topics

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