---
format: typebulb/v1
name: Sentiment Analyzer
---

**code.tsx**

```tsx
import {
  Module, Linear, LayerNorm, compileForward, checkWebGPU,
  add, sub, mul, div as divide, matmul, swapAxes, reshape, sum,
  splitHeads, mergeHeads, softmax, gelu, embedding,
  type Tensor,
} from 'tensorgrad'
import {
  App, Component, div, h1, h2, p, span, strong, ul, li, button, inputTextArea,
  type VElement,
} from 'domeleon'

// ============================================================================
//  Model & feature extraction (pure logic)
// ============================================================================

// all-MiniLM-L6-v2 dimensions (a 6-layer BERT encoder). The checkpoint is
// hosted 4-bit quantized on assets.typebulb.com (13 MB instead of the 90 MB
// f32 original; over the free per-bulb asset caps, so it lives at a shared
// absolute URL rather than in this bulb's assets/ folder); the pos/tokType
// tables are pre-sliced to exactly what this graph reads.
const D = 384
const H = 12
const HEADDIM = D / H
const DEPTH = 6
const FFN = 4 * D
const VOCAB = 30522
const MAXLEN = 64                       // pad/truncate every sentence to this; one compiled graph
const ENC_INPUTS = { ids: { shape: [1, MAXLEN], dtype: 'i32' }, mask: [1, MAXLEN] } as const

// BERT-uncased special token ids.
const PAD = 0, UNK = 100, CLS = 101, SEP = 102

const WEIGHTS_BASE = 'https://assets.typebulb.com/weights'

// The checkpoint's basename, shared by the hosted key and the local file.
const WEIGHTS_FILE = 'minilm-sentiment-v2.q4'
const VOCAB_FILE = 'all-MiniLM-L6-v2.vocab.txt'

// New weights get a new filename, never a rewritten one: republishing over a key leaves the CDN
// serving a stale manifest against the fresh binary, which loads as a checkpoint whose two halves
// disagree. This number also names the local cache, so bumping it retires copies already held.
const WEIGHTS_VERSION = 2

// Read the checkpoint from this bulb's assets folder through tb.fs (needs --trust) instead of the
// network, so a candidate can be measured without a 13 MB upload. Both paths read the same three
// filenames. Ships as false.
const LOCAL_WEIGHTS = false

// Display and label order: positive on top, negative at the bottom, neutral in
// between. The signed score below relies on positive being first and negative
// last.
const SENTIMENTS = ['positive', 'neutral', 'negative'] as const

const scoreOf = (probs: Float32Array) => probs[0]! - probs[SENTIMENTS.length - 1]!

// A passage is marked only when it leans this far, and then at one fixed strength. An earlier
// version varied intensity by confidence across all three classes, which meant grey came in four
// shades: "confidently neutral" and "barely neutral" both rendered as faint nothing, so the
// channel doing the most visual work was spent on the least useful axis. One threshold and one
// strength says a single thing — this passage leans, that way — and absence now carries the rest:
// no mark means neutral or undecided, which are the same non-event to a reader.
//
// Chosen from the distribution rather than taste: it is the median |score| over the segments of
// the sample text, so it marks about half of it. Carrying a value across a model change measures
// the threshold instead of the model, so re-derive it from the `marks` probe whenever the
// checkpoint moves. For this one the median is 0.71.
const HIGHLIGHT = 0.70

/** 'positive', 'negative', or '' when the segment doesn't lean far enough to say. */
const leaning = (score: number) => score >= HIGHLIGHT ? 'positive' : score <= -HIGHLIGHT ? 'negative' : ''

// Roosevelt's first inaugural, 4 March 1933, public domain as a US federal government work. The
// whole address rather than an excerpt, so there is no selection to defend, and at 1,876 words it
// exercises the windowing path (about 39 passes through the 64-token graph) the moment the page
// loads.
const SPEECH = tb.data(0).trim()
const SPEECH_PARAGRAPHS = SPEECH.split(/\r?\n\s*\r?\n/)
const SPEECH_SOURCE = 'Sample: Roosevelt\'s first inaugural, 1933'

interface Query { text: string; feat: Float32Array | null }

// ---- WordPiece tokenizer (BERT uncased) ------------------------------------
// Deterministic; the only non-network piece a text port needs. Basic tokenize
// (lowercase, strip accents, split on whitespace + punctuation) then greedy
// longest-match WordPiece against the 30k vocab.

function isPunct(ch: string): boolean {
  const c = ch.codePointAt(0)!
  if ((c >= 33 && c <= 47) || (c >= 58 && c <= 64) || (c >= 91 && c <= 96) || (c >= 123 && c <= 126)) return true
  return /\p{P}|\p{S}/u.test(ch)
}

function basicTokenize(text: string): string[] {
  const norm = text.trim().toLowerCase().normalize('NFD').replace(/[\u0300-\u036f]/g, '')
  const tokens: string[] = []
  let cur = ''
  for (const ch of norm) {
    if (/\s/.test(ch)) { if (cur) { tokens.push(cur); cur = '' } }
    else if (isPunct(ch)) { if (cur) { tokens.push(cur); cur = '' } tokens.push(ch) }
    else cur += ch
  }
  if (cur) tokens.push(cur)
  return tokens
}

function wordpiece(token: string, vocab: Map<string, number>): number[] {
  if (token.length > 100) return [UNK]
  const out: number[] = []
  let start = 0
  while (start < token.length) {
    let end = token.length
    let id = -1
    while (start < end) {
      const sub = (start > 0 ? '##' : '') + token.slice(start, end)
      const v = vocab.get(sub)
      if (v !== undefined) { id = v; break }
      end--
    }
    if (id === -1) return [UNK]          // any unmatchable piece -> whole token is [UNK]
    out.push(id)
    start = end
  }
  return out
}

// All content token ids for a text, no [CLS]/[SEP]; the embedder windows them.
function wordpieceIds(text: string, vocab: Map<string, number>): number[] {
  const out: number[] = []
  for (const tok of basicTokenize(text)) for (const id of wordpiece(tok, vocab)) out.push(id)
  return out
}

// ---- segmentation ----------------------------------------------------------
// Character ranges the model reads one at a time. They tile the text exactly —
// concatenated they reproduce it character for character — which is what lets a
// segment's verdict be painted behind the very words it was computed from.
//
// Sentence-aligned rather than a fixed token stride: a stride cuts mid-word, and
// a colour change landing inside "unemploy|ment" reads as a bug. The cost is one
// encoder pass per sentence instead of per 62 tokens.

/** Split on a sentence terminator plus the whitespace after it, or on line breaks.
 *  The trailing whitespace stays with the segment it follows, so nothing is orphaned. */
function sentenceSpans(text: string): [number, number][] {
  const spans: [number, number][] = []
  const re = /[.!?]["'’)\]]*\s+|\n+/g
  let start = 0
  for (let m = re.exec(text); m; m = re.exec(text)) {
    const end = m.index + m[0].length
    if (end > start) { spans.push([start, end]); start = end }
  }
  if (start < text.length) spans.push([start, text.length])
  return spans
}

/** Sentence spans, with any sentence too long for one pass broken at word boundaries. */
function fitSpans(text: string, vocab: Map<string, number>, maxTokens: number): [number, number][] {
  const out: [number, number][] = []
  for (const [s, e] of sentenceSpans(text)) {
    if (wordpieceIds(text.slice(s, e), vocab).length <= maxTokens) { out.push([s, e]); continue }
    let at = s, buf = ''
    for (const w of text.slice(s, e).match(/\S+\s*/g) ?? []) {
      if (buf && wordpieceIds(buf + w, vocab).length > maxTokens) {
        out.push([at, at + buf.length]); at += buf.length; buf = w
      } else buf += w
    }
    if (buf) out.push([at, at + buf.length])
  }
  return out.length ? out : [[0, text.length]]
}

// ---- MiniLM, features only (mean-pooled sentence embedding) -----------------

class Layer extends Module {
  q = new Linear(D, D)
  k = new Linear(D, D)
  v = new Linear(D, D)
  attnOut = new Linear(D, D)
  attnLN = new LayerNorm(D)
  inter = new Linear(D, FFN)
  out = new Linear(FFN, D)
  outLN = new LayerNorm(D)
}

class MiniLM extends Module {
  word = this.param([VOCAB, D])
  pos = this.param([MAXLEN, D])          // checkpoint rows 0..63, pre-sliced by the quantizer
  tokType = this.param([1, D])           // sentence-A row only
  embLN = new LayerNorm(D)
  blocks: Layer[]

  constructor() {
    super()
    this.blocks = Array.from({ length: DEPTH }, () => new Layer())
  }
}

// BERT is POST-norm: LayerNorm applies *after* each residual add. `bias` is
// the additive padding mask, broadcast over heads.
function layer(p: Layer, x: Tensor, bias: Tensor): Tensor {
  const q = splitHeads(p.q.fwd(x), H)
  const k = splitHeads(p.k.fwd(x), H)
  const v = splitHeads(p.v.fwd(x), H)
  const scores = add(mul(matmul(q, swapAxes(k, -1, -2)), 1 / Math.sqrt(HEADDIM)), bias)
  const ctx = mergeHeads(matmul(softmax(scores, -1), v))
  const a = p.attnLN.fwd(add(x, p.attnOut.fwd(ctx)))
  return p.outLN.fwd(add(a, p.out.fwd(gelu(p.inter.fwd(a)))))
}

// word + position + token-type embeddings -> LayerNorm -> blocks -> masked mean.
function encode(m: MiniLM, { ids, mask }: { ids: Tensor; mask: Tensor }): Tensor {
  let h = add(add(embedding(m.word, ids), m.pos), m.tokType)
  h = m.embLN.fwd(h)
  const bias = reshape(mul(sub(mask, 1), 1e9), [1, 1, 1, MAXLEN])   // 0 at real tokens, -1e9 at pads
  for (const b of m.blocks) h = layer(b, h, bias)
  const m3 = reshape(mask, [1, MAXLEN, 1])
  return divide(sum(mul(h, m3), 1), sum(m3, 1))                     // [1, D] masked mean over tokens
}

// ---- the 4-bit checkpoint --------------------------------------------------
// Produced offline by the quantizer that publishes these weights: a manifest
// naming each tensor and a packed binary. Big matrices are symmetric int4 in
// groups of 64 with one f32 scale per group (two values per byte, biased to
// 0..15); everything small stays f32. Names/shapes already match this Module,
// so unpacking is the whole import.

interface QTensor { name: string; shape: number[]; kind: 'q4' | 'f32'; dataOffset: number; scalesOffset?: number }
interface Manifest { groupSize: number; tensors: QTensor[]; totalBytes: number }

function unpackParams(manifest: Manifest, buf: ArrayBuffer): Record<string, Float32Array> {
  const out: Record<string, Float32Array> = {}
  for (const t of manifest.tensors) {
    const n = t.shape.reduce((a, b) => a * b, 1)
    if (t.kind === 'f32') {
      out[t.name] = new Float32Array(buf, t.dataOffset, n)
      continue
    }
    const packed = new Uint8Array(buf, t.dataOffset, n / 2)
    const scales = new Float32Array(buf, t.scalesOffset!, n / manifest.groupSize)
    const v = new Float32Array(n)
    for (let i = 0; i < n; i += 2) {
      const s = scales[(i / manifest.groupSize) | 0]!
      const byte = packed[i >> 1]!
      v[i] = ((byte & 15) - 8) * s
      v[i + 1] = ((byte >> 4) - 8) * s
    }
    out[t.name] = v
  }
  return out
}

// Fetch once from the network, thereafter from CacheStorage. The checkpoint is
// immutable, so re-downloading 13 MB on every open is pure latency. Falls back
// to a plain fetch wherever the Cache API isn't available. CacheStorage is the
// only cache layer: `no-store` keeps the HTTP cache out of it, so a stale
// edge/browser 404 (e.g. a visit that raced the asset upload) can't stick.
async function cachedFetch(
  url: string,
  onProgress?: (received: number, total: number) => void,
): Promise<ArrayBuffer> {
  const download = async (): Promise<ArrayBuffer> => {
    for (let attempt = 0; ; attempt++) {
      try {
        const res = await fetch(url, { cache: 'no-store' })
        if (!res.ok) throw new Error(`fetch ${url} -> ${res.status}`)
        const total = Number(res.headers.get('content-length')) || 0
        // Read the body chunk by chunk so the loading bar is real bytes. No
        // Content-Length (a proxy stripped it) means no honest fraction, so
        // fall back to the one-shot read and let the caller stay coarse.
        if (!res.body || !onProgress || !total) return await res.arrayBuffer()
        const reader = res.body.getReader()
        const chunks: Uint8Array[] = []
        let got = 0
        for (;;) {
          const { done, value } = await reader.read()
          if (done) break
          chunks.push(value)
          got += value.byteLength
          onProgress(got, total)
        }
        const out = new Uint8Array(got)
        let off = 0
        for (const c of chunks) { out.set(c, off); off += c.byteLength }
        return out.buffer as ArrayBuffer
      } catch (e) {
        if (attempt >= 1) throw e
        onProgress?.(0, 0)                 // retrying: this file's bytes are moot
        await new Promise(r => setTimeout(r, 1000))
      }
    }
  }
  try {
    const CACHE = `sentiment-weights-v${WEIGHTS_VERSION}`
    // Drop this bulb's earlier caches, so a bump reclaims their space instead of stacking.
    for (const name of await caches.keys()) {
      if (name.startsWith('sentiment-') && name !== CACHE) await caches.delete(name)
    }
    const cache = await caches.open(CACHE)
    const hit = await cache.match(url)
    if (hit) {
      const buf = await hit.arrayBuffer()
      onProgress?.(buf.byteLength, buf.byteLength)   // already here: this file is done
      return buf
    }
    const buf = await download()
    try { await cache.put(url, new Response(buf)) } catch { /* caching is an optimisation */ }
    return buf
  } catch {
    return download()
  }
}

function l2normalize(v: Float32Array): Float32Array {
  let norm = 0
  for (const x of v) norm += x * x
  norm = Math.sqrt(norm) || 1
  const out = new Float32Array(v.length)
  for (let i = 0; i < v.length; i++) out[i] = v[i]! / norm
  return out
}

// A bulb asset read into a *fresh* ArrayBuffer starting at offset 0. unpackParams builds typed
// array views at the manifest's byte offsets, and those are only 4-byte aligned relative to the
// start of the packed blob, so a Uint8Array that happens to sit part-way into a larger buffer
// would throw on the first f32 tensor.
async function localBytes(name: string): Promise<ArrayBuffer> {
  const u8 = await tb.fs.readBytes(name)
  const buf = new ArrayBuffer(u8.byteLength)
  new Uint8Array(buf).set(u8)
  return buf
}

// The classifier: one linear layer over the L2-normalised 384-d feature, trained offline on the
// same corpus as the encoder and shipped inside the same checkpoint as `fc.W` and `fc.b`. The
// logit scale it was trained under is already folded into those weights, so this softmax is
// exactly the function the offline evaluation measured.
class Head extends Module {
  fc = new Linear(D, SENTIMENTS.length)
}

async function loadHead(params: Record<string, Float32Array>) {
  const head = await compileForward({
    model: new Head(),
    forward: (m: Head, { f }: { f: Tensor }) => softmax(m.fc.fwd(f), -1),
    inputs: { f: [1, D] },
  })
  const own = Object.fromEntries((head.paramNames as readonly string[])
    .map(n => [n, params[n]]).filter(([, v]) => v)) as Record<string, Float32Array>
  const missing = (head.paramNames as readonly string[]).filter(n => !(n in own))
  if (missing.length) throw new Error(`checkpoint has no classifier: missing ${missing.join(', ')}`)
  await head.uploadParams(own)
  return head
}

// ============================================================================
//  Model — app state + the ML pipeline (a non-visual domeleon component)
// ============================================================================

// Startup is measurable nearly end to end — bytes off the wire, then unpacking and upload — so the
// loading bar is a true fraction rather than a timer pretending to be one. Compilation is the one
// opaque stretch (no progress to read out of a single await), so it gets three coarse ticks rather
// than a share of the bar it can't account for.
const BANDS = {
  download: [0.00, 0.72],
  compile: [0.72, 0.99],
} as const

// Let the browser paint a freshly-set label before we block the thread on a
// long synchronous stretch (unpacking 23M weights).
const yieldToPaint = () => new Promise(r => setTimeout(r, 0))

class Model extends Component {
  status = 'starting…'
  progress = 0                           // 0..1, monotonic across startup
  failed = false
  ready = false
  query: Query | null = null
  probs: Float32Array | null = null
  // Windows of a long text embedded so far — a pasted essay is more than one
  // pass through the 64-token graph, so the wait is worth counting too.
  embedDone = 0
  embedTotal = 0
  // Verdict per segment with the character range it was read from and how sure it was: the raw
  // material for both the wash behind the text and the overview ruler's bands.
  segments: { start: number; end: number; pred: number; p: number; score: number }[] = []

  #backbone: Awaited<ReturnType<typeof compileForward<MiniLM, typeof ENC_INPUTS>>> | null = null
  #head: Awaited<ReturnType<typeof loadHead>> | null = null
  #vocab: Map<string, number> = new Map()
  #started = false
  #band?: keyof typeof BANDS
  // Bumped by every new analysis and by any edit. An in-flight run compares it against the value
  // it started with, so a superseded run stops at its next segment instead of spending the GPU on
  // a result nobody wants and then overwriting a newer one.
  #run = 0
  // Settles on every exit of start(), success or failure, so a probe that
  // awaits readiness never hangs. True means the pipeline is usable.
  #ready: Promise<boolean> = Promise.resolve(false)

  override onAttached() {
    if (this.#started) return
    this.#started = true
    this.#ready = this.start()
  }

  whenReady(): Promise<boolean> { return this.#ready }

  // A run is in flight: the query is set but its verdict has not landed. Drives the read-only
  // state of the editor and the disabled state of the button, so neither can change the text out
  // from under a run that is still reading it.
  get analyzing(): boolean { return this.ready && this.query !== null && this.probs === null }

  /** Identity of the current analysis. Changes on every new run and on every cancel, which is how
   *  the view knows a fresh run has begun without the model having to reach into it. */
  get runId(): number { return this.#run }

  setStatus(s: string) {
    this.status = s
    tb.log(s)
    this.update()
  }

  // Sub-ticks are silent; entering a phase logs once.
  setProgress(band: keyof typeof BANDS, sub: number, text: string) {
    const [a, b] = BANDS[band]
    this.progress = a + (b - a) * Math.max(0, Math.min(1, sub))
    this.status = text
    if (band !== this.#band) { this.#band = band; tb.log(text) }
    this.update()
  }

  async start(): Promise<boolean> {
    try {
      const gpu = await checkWebGPU()
      if (!gpu.ok) {
        this.failed = true
        this.setStatus(gpu.message)
        return false
      }

      // Three files in flight at once, so the fraction is their summed bytes.
      // Sizes only firm up once every response has reported one, which is why
      // the label stays byte-less until then.
      const got = [0, 0, 0]
      const size = [0, 0, 0]
      const sum = (a: number[]) => a.reduce((x, y) => x + y, 0)
      const mb = (n: number) => (n / 1e6).toFixed(1)
      let shown = -1
      const onBytes = (i: number) => (received: number, total: number) => {
        got[i] = received
        size[i] = total
        const known = size.every(s => s > 0)
        // Chunks arrive ~200 times for 13 MB; repaint only when the whole
        // number moves, so measuring costs a render per percent, not per chunk.
        const pct = known ? Math.round((sum(got) / sum(size)) * 100) : -1
        if (pct === shown) return
        shown = pct
        this.setProgress('download', known ? sum(got) / sum(size) : 0,
          known ? `Downloading the model (${mb(sum(got))} of ${mb(sum(size))} MB)`
            : 'Downloading the model…')
      }
      this.setProgress('download', 0, 'Downloading the model…')
      const [manifestBuf, bin, vocabBuf] = LOCAL_WEIGHTS
        ? await (async () => {
            this.setProgress('download', 0.5, 'Reading the local checkpoint…')
            return Promise.all([
              localBytes(`${WEIGHTS_FILE}.json`),
              localBytes(`${WEIGHTS_FILE}.bin`),
              localBytes(VOCAB_FILE),
            ])
          })()
        : await Promise.all([
            cachedFetch(`${WEIGHTS_BASE}/${WEIGHTS_FILE}.json`, onBytes(0)),
            cachedFetch(`${WEIGHTS_BASE}/${WEIGHTS_FILE}.bin`, onBytes(1)),
            cachedFetch(`${WEIGHTS_BASE}/${VOCAB_FILE}`, onBytes(2)),
          ])
      const manifest = JSON.parse(new TextDecoder().decode(manifestBuf)) as Manifest
      if (bin.byteLength !== manifest.totalBytes) throw new Error('truncated checkpoint')
      new TextDecoder().decode(vocabBuf).split(/\r?\n/).forEach((tok, i) => { if (tok) this.#vocab.set(tok, i) })

      this.setProgress('compile', 0, 'Unpacking the weights…')
      await yieldToPaint()
      const params = unpackParams(manifest, bin)
      this.setProgress('compile', 0.25, 'Compiling the graph…')
      this.#backbone = await compileForward({ model: new MiniLM(), forward: encode, inputs: ENC_INPUTS })
      // One checkpoint carries two models: the encoder and the classifier that reads it. Split by
      // name before uploading, since uploadParams is strict both ways and would reject the head's
      // tensors as unexpected. A mismatch surfaces as a readable diff rather than whatever error
      // the library raises first.
      const encoderNames = new Set(this.#backbone.paramNames as readonly string[])
      const encoderParams: Record<string, Float32Array> = {}
      const headParams: Record<string, Float32Array> = {}
      for (const [name, value] of Object.entries(params)) {
        (encoderNames.has(name) ? encoderParams : headParams)[name] = value
      }
      const missing = [...encoderNames].filter(n => !(n in encoderParams))
      if (missing.length) throw new Error(`checkpoint is missing encoder weights: ${missing.join(', ')}`)
      this.setProgress('compile', 0.7, 'Uploading the weights to the GPU…')
      await this.#backbone.uploadParams(encoderParams)

      this.setProgress('compile', 0.9, 'Loading the classifier…')
      this.#head = await loadHead(headParams)
      this.progress = 1
      this.ready = true
      this.status = ''
      await this.preselect()
      tb.log('Ready.')
      return true
    } catch (err) {
      this.failed = true
      this.setStatus(`Something broke while starting: ${(err as Error).message}`)
      return false
    }
  }

  // The compiled graph reads MAXLEN tokens, so a longer text is embedded a segment at a time and
  // token-weight averaged: a masked token mean per segment, weighted by its length, is the token
  // mean over the whole text.
  //
  // `onSegment` doubles as the opt-in for per-segment classification: one extra 384x3 matmul
  // against a full six-layer encoder pass, so the map is close to free. Callers that only want the
  // whole-text feature pass nothing and skip it.
  async embOf(
    text: string,
    onSegment?: (done: number, total: number, pred: number, p: number, score: number, start: number, end: number) => void | boolean,
  ): Promise<Float32Array> {
    const spans = fitSpans(text, this.#vocab, MAXLEN - 2)
    onSegment?.(0, spans.length, -1, 0, 0, 0, 0)
    const acc = new Float64Array(D)
    let total = 0
    for (let i = 0; i < spans.length; i++) {
      const [from, to] = spans[i]!
      const slice = wordpieceIds(text.slice(from, to), this.#vocab).slice(0, MAXLEN - 2)
      const ids = new Int32Array(MAXLEN)   // pad with PAD (0)
      const mask = new Float32Array(MAXLEN)
      ids[0] = CLS
      for (let j = 0; j < slice.length; j++) ids[j + 1] = slice[j]!
      ids[slice.length + 1] = SEP
      for (let j = 0; j < slice.length + 2; j++) mask[j] = 1
      const r = await this.#backbone!.run({ ids, mask })
      if (r.kind !== 'completed') throw new Error(`embed run ${r.kind}`)
      const out = r.output as Float32Array
      const w = slice.length + 2
      for (let j = 0; j < D; j++) acc[j]! += out[j]! * w
      total += w
      // Normalized the way the whole-text feature is, so the head sees the distribution it was
      // fitted on rather than an unscaled segment mean.
      let pred = -1
      let conf = 0
      let score = 0
      if (onSegment && this.#head) {
        const sp = await this.probsOf(l2normalize(out.slice(0, D)))
        pred = 0
        for (let k = 1; k < sp.length; k++) if (sp[k]! > sp[pred]!) pred = k
        conf = sp[pred]!
        score = scoreOf(sp)
      }
      // A callback returning false has decided this run is stale; the partial mean is discarded
      // by the caller, which checks the same token before using it.
      if (onSegment?.(i + 1, spans.length, pred, conf, score, from, to) === false) break
    }
    const mean = new Float32Array(D)
    for (let j = 0; j < D; j++) mean[j] = acc[j]! / (total || 1)
    return l2normalize(mean)
  }

  async probsOf(feat: Float32Array): Promise<Float32Array> {
    const r = await this.#head!.run({ f: feat })
    if (r.kind !== 'completed') throw new Error(`classify run ${r.kind}`)
    return r.output as Float32Array
  }

  async classify() {
    if (!this.#head || !this.query?.feat) return
    try {
      this.probs = await this.probsOf(this.query.feat)
    } catch (err) {
      tb.log((err as Error).message)
      return
    }
    this.update()
  }

  // Editing invalidates whatever is being computed. An analysis still running is stopped and its
  // half-drawn readout removed, since a progress bar for text that has since changed is worse than
  // no readout at all. A finished verdict is left standing so it can still be read.
  cancel() {
    this.#run++
    if (this.probs === null) this.query = null
    this.segments = []
    this.embedDone = 0
    this.embedTotal = 0
    this.update()
  }

  async classifyText(text: string) {
    if (!this.ready) return
    const run = ++this.#run
    try {
      this.query = { text, feat: null }
      this.probs = null
      this.embedDone = 0
      this.embedTotal = 0
      this.segments = []
      this.update()
      // Same repaint guard as the download: a pasted essay is hundreds of
      // windows, and the bar only has a hundred positions to show.
      let shown = -1
      const feat = await this.embOf(text, (d, t, pred, p, score, from, to) => {
        if (run !== this.#run) return false
        this.embedDone = d
        this.embedTotal = t
        if (pred >= 0) this.segments.push({ start: from, end: to, pred, p, score })
        const pct = Math.round((d / t) * 100)
        if (pct === shown && d > 0) return
        shown = pct
        this.update()
      })
      if (run !== this.#run) return
      if (this.query) this.query.feat = feat
      await this.classify()
    } catch (err) {
      tb.log(`couldn't embed text: ${(err as Error).message}`)
    }
  }

  async preselect() {
    try {
      // Straight through classifyText rather than a second copy of it, so the launch example
      // builds its window map exactly as typed text does. Reached only after ready is set.
      await this.classifyText(SPEECH)
    } catch {
      this.query = null
      this.update()
    }
  }

  // ---- terminal probes (typebulb send) -------------------------------------

  async classifyProbe(text: string) {
    if (!await this.#ready) return { error: this.status }
    const probs = await this.probsOf(await this.embOf(text))
    let pred = 0
    for (let i = 1; i < probs.length; i++) if (probs[i]! > probs[pred]!) pred = i
    return {
      verdict: SENTIMENTS[pred]!,
      score: +scoreOf(probs).toFixed(3),
      probs: Object.fromEntries(SENTIMENTS.map((s, i) => [s, +probs[i]!.toFixed(3)])),
    }
  }

  // Reads every paragraph of the speech on its own, then the whole thing, so
  // the question "is the full address genuinely balanced, or is mean-pooling
  // just washing it out?" is answered with numbers instead of a hunch. Takes no
  // argument: the text is already in data.txt.
  async paragraphProbe() {
    if (!await this.#ready) return { error: this.status }
    const read = async (text: string) => {
      const probs = await this.probsOf(await this.embOf(text))
      let pred = 0
      for (let i = 1; i < probs.length; i++) if (probs[i]! > probs[pred]!) pred = i
      return {
        verdict: SENTIMENTS[pred]!,
        pct: Object.fromEntries(SENTIMENTS.map((s, i) => [s, Math.round(probs[i]! * 100)])),
        score: +scoreOf(probs).toFixed(3),
      }
    }
    type Row = { n: number; words: number; head: string } & Awaited<ReturnType<typeof read>>
    const paragraphs: Row[] = []
    for (let i = 0; i < SPEECH_PARAGRAPHS.length; i++) {
      const p = SPEECH_PARAGRAPHS[i]!
      paragraphs.push({ n: i + 1, words: p.split(/\s+/).length, ...await read(p), head: p.slice(0, 44) })
    }
    const scores = paragraphs.map(p => p.score)
    const mean = scores.reduce((a, b) => a + b, 0) / scores.length
    return {
      paragraphs,
      spread: {
        minScore: +Math.min(...scores).toFixed(3),
        maxScore: +Math.max(...scores).toFixed(3),
        meanScore: +mean.toFixed(3),
        sd: +Math.sqrt(scores.reduce((a, s) => a + (s - mean) ** 2, 0) / scores.length).toFixed(3),
        verdicts: Object.fromEntries(SENTIMENTS.map(s =>
          [s, paragraphs.filter(p => p.verdict === s).length])),
      },
      whole: await read(SPEECH),
    }
  }
}

// ============================================================================
//  UI
// ============================================================================

/** A band of interest in content space: both values are fractions of the container's scrollHeight. */
interface RulerMark { top: number; height: number; class?: string }

interface RulerOptions {
  class?: string
  title?: string
  /** Accessible name. The track reports as a scrollbar, so it needs one. */
  label?: string
  /** id of the scroll container, for aria-controls. */
  controls?: string
}

// Copied from typebulb's own agent mirror (runtime/cli/agents/core/client/overviewRuler.ts),
// where it maps added and deleted lines onto a diff's scrollbar. A bulb can't import from the
// runtime, so it travels by copy; keep it in step by hand if the original changes.
//
// A scrollbar-shaped map of a scroll container: a thin vertical track carrying caller-supplied
// marks, plus a window showing what's currently on screen. Press to centre there, then drag; the
// wheel works over the track as it would over a real bar.
//
// It REPLACES the container's scrollbar rather than sitting beside it, which is the point rather
// than a flourish: every engine fattens a small thumb to a minimum length, and the shortened travel
// that buys makes the thumb's position a different function of scrollTop than any track drawn
// alongside it. Owning both ends puts marks and window in one coordinate system (a mark under the
// window IS on screen) and leaves no browser scrollbar metric anywhere in the geometry.
//
// Not a domeleon Component: the window moves on every scroll event, which wants a style write on one
// node, not a re-render. The host holds an instance, renders view(), calls sync() when the container
// scrolls or its content changes, and release() when the scroll surface goes away.
class OverviewRuler {
  #scroller: () => HTMLElement | undefined
  #track?: HTMLElement
  #win?: HTMLElement
  #queued = false
  #grab?: number                 // mid-drag: the pointer's offset from the window's top, in track px
  #resize?: ResizeObserver

  constructor(scroller: () => HTMLElement | undefined) { this.#scroller = scroller }

  // Taking the bar away is the widget's own act, not a stylesheet's: it happens when the replacement
  // mounts, and again on every sync so a host re-render that rewrites `class` can't undo it.
  #own() { this.#scroller()?.classList.add('oruler-host') }

  #mount(track: HTMLElement) {
    this.#track = track
    const el = this.#scroller()
    if (!el) return
    this.#own()
    this.#resize?.disconnect()
    this.#resize = new ResizeObserver(() => this.sync())
    this.#resize.observe(el)
    this.sync()
  }

  // Repaint the window from the container's live geometry — idempotent, and rAF-coalesced so a burst
  // of scroll events costs one write per frame.
  sync() {
    if (this.#queued) return
    this.#queued = true
    requestAnimationFrame(() => {
      this.#queued = false
      const el = this.#scroller(), win = this.#win
      if (!el || !win || !el.scrollHeight) return
      this.#own()
      const max = el.scrollHeight - el.clientHeight
      win.style.display = max > 0 ? '' : 'none'
      win.style.top = `${(el.scrollTop / el.scrollHeight) * 100}%`
      win.style.height = `${(el.clientHeight / el.scrollHeight) * 100}%`
      this.#track?.setAttribute('aria-valuenow', String(max > 0 ? Math.round((el.scrollTop / max) * 100) : 0))
    })
  }

  // role=scrollbar, no tabIndex — matching what it stands in for: a native bar is no tab stop either,
  // and the scroll container is the focusable element carrying the paging keys.
  // The window renders FIRST so its index stays 0 as the mark list grows and shrinks.
  view(marks: RulerMark[], opts: RulerOptions = {}): VElement {
    return div({
        class: ['oruler', opts.class ?? ''],
        title: opts.title,
        role: 'scrollbar',
        ariaOrientation: 'vertical',
        ariaLabel: opts.label ?? 'Scroll position',
        ariaControls: opts.controls,
        ariaValueMin: 0, ariaValueMax: 100, ariaValueNow: 0,
        onMounted: (el: Element) => this.#mount(el as HTMLElement),
        onPointerDown: (e: PointerEvent) => this.#down(e),
        onPointerMove: (e: PointerEvent) => this.#move(e),
        onPointerUp: (e: PointerEvent) => this.#up(e),
        onPointerCancel: (e: PointerEvent) => this.#up(e),
        onWheel: (e: WheelEvent) => this.#wheel(e),
      },
      div({ class: 'oruler-win', onMounted: (el: Element) => { this.#win = el as HTMLElement; this.sync() } }),
      marks.map(m => div({
        class: ['oruler-mark', m.class ?? ''],
        style: { top: `${m.top * 100}%`, height: `${m.height * 100}%` },
      })),
    )
  }

  // Pointer-down starts a drag: on the window it takes hold where you grabbed it, anywhere else the
  // window centres under the pointer first — plain click-to-jump when you don't then move.
  #down(e: PointerEvent) {
    const el = this.#scroller(), track = e.currentTarget as HTMLElement
    if (!el) return
    e.preventDefault()                                     // no text selection while dragging
    const win = this.#win?.getBoundingClientRect()
    const onWin = !!win && e.clientY >= win.top && e.clientY <= win.bottom
    this.#grab = onWin ? e.clientY - win!.top : (win?.height ?? 0) / 2
    track.setPointerCapture(e.pointerId)
    this.#scrollTo(e, track, el)
  }

  #move(e: PointerEvent) {
    const el = this.#scroller()
    if (this.#grab === undefined || !el) return
    this.#scrollTo(e, e.currentTarget as HTMLElement, el)
  }

  #up(e: PointerEvent) {
    const track = e.currentTarget as HTMLElement
    this.#grab = undefined
    if (track.hasPointerCapture(e.pointerId)) track.releasePointerCapture(e.pointerId)
  }

  // A native bar scrolls its container when the wheel turns over it. Ours is an overlay, not an
  // ancestor of the scroller, so the event would otherwise find nothing scrollable and do nothing.
  #wheel(e: WheelEvent) {
    const el = this.#scroller()
    if (!el) return
    const step = e.deltaMode === 1 ? 16 : e.deltaMode === 2 ? el.clientHeight : 1
    el.scrollTop += e.deltaY * step
    this.sync()
  }

  // Where the window's top lands is what sets scrollTop — the inverse of the map sync() paints with,
  // so the drag can't drift from the thing being dragged. scrollTop clamps itself at either end.
  #scrollTo(e: PointerEvent, track: HTMLElement, el: HTMLElement) {
    const top = e.clientY - track.getBoundingClientRect().top - (this.#grab ?? 0)
    el.scrollTop = (top / track.clientHeight) * el.scrollHeight
    this.sync()
  }
}

class Root extends Component {
  model = new Model()
  draft = SPEECH
  tab: 'analyzer' | 'about' = 'analyzer'
  ruler = new OverviewRuler(() => this.#textEl)
  #textEl?: HTMLTextAreaElement
  #mirrorEl?: HTMLElement
  // Follow the scan down the page while it reads, until the reader takes the wheel. Reset per run
  // rather than per render, so stopping it stays stopped for the rest of that analysis.
  #tracking = true
  #seenRun = -1

  /** Any deliberate move by the reader ends the follow for this run: once they have taken control
   *  of where they are looking, yanking the view elsewhere is the rudest thing the page could do. */
  stopTracking() { this.#tracking = false }

  // Keep the segment being read about two thirds down the pane, and only ever scroll forward: the
  // scan advances monotonically, so reacting to it that way can never jitter or scroll back.
  followScan() {
    const el = this.#textEl
    const text = this.analyzedText()
    const segs = this.model.segments
    if (!el || !text.length || !segs.length || !el.scrollHeight) return
    // Character fraction, not a measured position: the scan only needs to stay roughly in view,
    // and a blank line here or there costing a line of drift is invisible at this speed.
    const y = (segs[segs.length - 1]!.end / text.length) * el.scrollHeight
    const lead = el.clientHeight * 0.65
    if (y - el.scrollTop > lead) el.scrollTop = y - lead
  }

  // The text the current segments were read from. Once the draft diverges from it, the wash and
  // the map describe words that are no longer there, so both drop out rather than sit misaligned.
  analyzedText(): string {
    const t = this.model.query?.text
    return t !== undefined && t === this.draft ? t : ''
  }

  // Segments carry exact character ranges, so a band is a character fraction of the text rather
  // than a guess from its index. Still not pixel exact: a blank line between paragraphs costs a
  // line of height but only a character or two, so a band can sit a line off on heavily
  // paragraphed text.
  //
  // Only leaning segments get a band, at one flat strength, and adjacent ones the same way merge.
  // The gaps are the point: an unmarked stretch is text the model had nothing to say about.
  rulerMarks(): RulerMark[] {
    const segs = this.model.segments
    const len = this.analyzedText().length
    if (!segs.length || !len) return []
    const out: RulerMark[] = []
    let i = 0
    while (i < segs.length) {
      const lean = leaning(segs[i]!.score)
      if (!lean) { i++; continue }
      let j = i
      while (j + 1 < segs.length && leaning(segs[j + 1]!.score) === lean) j++
      out.push({ top: segs[i]!.start / len, height: (segs[j]!.end - segs[i]!.start) / len, class: lean })
      i = j + 1
    }
    return out
  }

  // A copy of the text laid exactly under the real one, carrying the wash and nothing else: its
  // glyphs are transparent, so what shows through is the textarea's own text over these
  // backgrounds. The textarea keeps caret, selection, undo, IME and paste, which is the whole
  // reason for painting behind it rather than replacing it with a contenteditable.
  mirror() {
    const text = this.analyzedText()
    const segs = this.model.segments
    this.queueAlign()
    // Hidden from assistive tech: these glyphs are a duplicate of the textarea's own content,
    // present only to carry the wash. Without this a screen reader reads the whole text twice.
    const attrs = {
      class: 'text-mirror',
      ariaHidden: true,
      onMounted: (el: Element) => { this.#mirrorEl = el as HTMLElement },
    }
    if (!text || !segs.length) return div(attrs)
    const parts: VElement[] = []
    let at = 0
    for (const s of segs) {
      if (s.start > at) parts.push(span(text.slice(at, s.start)))
      const lean = leaning(s.score)
      const body = text.slice(s.start, s.end)
      parts.push(lean ? span({ class: `wash ${lean}` }, body) : span(body))
      at = s.end
    }
    // Trailing newline: a textarea keeps a final empty line, and the mirror must agree or the
    // two scroll heights drift apart by one line.
    parts.push(span(`${text.slice(at)}\n`))
    return div(attrs, parts)
  }

  syncScroll() {
    if (this.#mirrorEl && this.#textEl) this.#mirrorEl.scrollTop = this.#textEl.scrollTop
  }

  // The mirror is a fresh scroll container every time its content changes, so it starts at the top
  // while the textarea may be scrolled well down — the wash then sits offset until any scroll event
  // happens to resync it. Realigning after the DOM settles is what makes the highlight correct on
  // the first paint rather than the first scroll. rAF-coalesced: renders come in bursts as segments
  // stream in, and one alignment per frame is enough.
  #alignQueued = false
  queueAlign() {
    if (this.#alignQueued) return
    this.#alignQueued = true
    requestAnimationFrame(() => {
      this.#alignQueued = false
      if (this.#seenRun !== this.model.runId) {
        this.#seenRun = this.model.runId
        this.#tracking = true
        // A run reads from the top, so the view starts there. Without this the follow looked dead
        // on pasted text: a paste leaves the caret, and the scroll, at the end of what was pasted,
        // and a forward-only follow has nothing to do until the scan reaches that point. Guarded
        // on analyzing so the run-id bump that every keystroke causes can't yank the pane to the
        // top while someone is editing.
        if (this.model.analyzing && this.#textEl) this.#textEl.scrollTop = 0
      }
      if (this.#tracking && this.model.analyzing) this.followScan()
      this.syncScroll()
      this.ruler.sync()
    })
  }

  classifyDraft() {
    // Analyse the draft exactly as it stands. Trimming first would make the segments' character
    // offsets index a string the editor isn't showing, and the wash and ruler — which key off
    // query.text matching the draft — would silently drop out for any text with surrounding
    // whitespace, which pasted text almost always has.
    if (!this.draft.trim()) return
    this.model.classifyText(this.draft)
  }

  view() {
    return div({ class: 'app' },
      div({ class: 'header' },
        h1('Sentiment Analyzer'),
        p({ class: 'tagline' }, 'Analyzes tone with a 23 million parameter neural network, loaded into your browser.'),
      ),
      this.tabs(),
      this.tab === 'analyzer' ? this.stage() : this.about(),
    )
  }

  tabs() {
    return div({ class: 'tabs' },
      this.tabButton('analyzer', 'Analyzer'),
      this.tabButton('about', 'How it works'),
    )
  }

  tabButton(id: 'analyzer' | 'about', label: string) {
    return button({
      class: this.tab === id ? 'tab active' : 'tab',
      onClick: () => { this.tab = id; this.update() },
    }, label)
  }

  stage() {
    if (!this.model.ready) {
      return this.loading()
    }
    return div({ class: 'analyzer' },
      this.composer(),
      this.model.query ? this.readout() : null,
    )
  }

  loading() {
    if (this.model.failed) {
      return div({ class: 'loading' }, p({ class: 'loading-lead' }, this.model.status))
    }
    const pct = Math.round(this.model.progress * 100)
    return div({ class: 'loading' },
      p({ class: 'loading-lead' }, 'Loading a sentiment model into your browser. It runs locally on your device.'),
      div({ class: 'progress' },
        div({ class: 'progress-track' },
          div({ class: 'progress-fill', style: { width: `${pct}%` } })),
        div({ class: 'progress-row' },
          span({ class: 'progress-step' }, this.model.status || 'Warming up…'),
          span({ class: 'progress-pct' }, `${pct}%`)),
      ),
    )
  }

  composer() {
    return div({ class: 'composer' },
      div({
          class: 'text-wrap',
          // Wheel, drag and touch all mean the same thing here, and the ruler's own drag bubbles
          // through this wrapper, so one place catches every way of taking the view over.
          onWheel: () => this.stopTracking(),
          onPointerDown: () => this.stopTracking(),
          onTouchMove: () => this.stopTracking(),
        },
        this.mirror(),
        inputTextArea({
          target: this,
          prop: () => this.draft,
          attrs: {
            class: 'text-input',
            placeholder: 'Paste an essay or type a sentence. Enter analyzes, Shift+Enter is a newline…',
            rows: 10,
            // readOnly, not disabled: a disabled textarea cannot be scrolled, and scrolling is
            // exactly what you want while the wash and the ruler fill in beneath you. It is an
            // HTML boolean attribute, so presence is the truth and undefined is how it comes off.
            readOnly: this.model.analyzing ? 'readonly' : undefined,
            onMounted: (el: Element) => { this.#textEl = el as HTMLTextAreaElement; this.ruler.sync() },
            onScroll: () => { this.syncScroll(); this.ruler.sync() },
            onInput: () => { this.model.cancel(); this.syncScroll(); this.ruler.sync() },
            onKeyDown: (e: KeyboardEvent) => {
              // The pane is read-only mid-run, but the paging and arrow keys still scroll it.
              if (['ArrowUp', 'ArrowDown', 'PageUp', 'PageDown', 'Home', 'End'].includes(e.key)) this.stopTracking()
              if (e.key === 'Enter' && !e.shiftKey) { e.preventDefault(); this.classifyDraft() }
            },
          },
        }),
        this.ruler.view(this.rulerMarks(), {
          class: 'text-ruler',
          label: 'Sentiment through the text',
          title: 'Sentiment through the text',
        }),
      ),
      div({ class: 'composer-foot' },
        span({ class: 'hint' },
          this.draft === SPEECH ? `${SPEECH_SOURCE} · Enter to analyze` : 'Enter to analyze'),
        button({
          class: 'classify-btn',
          disabled: this.model.analyzing,
          onClick: () => this.classifyDraft(),
        }, this.model.analyzing ? 'Analyzing…' : 'Analyze'),
      ),
    )
  }

  readout() {
    const { probs } = this.model
    if (!probs) {
      const { embedDone, embedTotal } = this.model
      // One window is over before a bar would render; an essay is hundreds, so
      // it gets the same measured treatment as startup.
      if (embedTotal > 1) {
        const pct = Math.round((embedDone / embedTotal) * 100)
        return div({ class: 'readout' },
          div({ class: 'progress result' },
            div({ class: 'progress-track' },
              div({ class: 'progress-fill', style: { width: `${pct}%` } })),
            div({ class: 'progress-row' },
              span({ class: 'progress-step' }, `Analyzing part ${Math.min(embedDone + 1, embedTotal)} of ${embedTotal}`),
              span({ class: 'progress-tail' },
                span({ class: 'progress-pct' }, `${pct}%`),
                // Typing already cancels, but that is a thing you have to find out. A control
                // that says so is the difference between a feature and a rumour.
                button({
                  class: 'stop-btn',
                  ariaLabel: 'Stop analyzing',
                  title: 'Stop analyzing',
                  onClick: () => this.model.cancel(),
                }, span({ class: 'stop-glyph' })),
              )),
          ),
        )
      }
      return div({ class: 'readout' },
        div({ class: 'readout-wait' }, span({ class: 'spinner' }), 'analyzing the text…'),
      )
    }
    return div({ class: 'readout' }, this.valenceStrip())
  }

  // How much of the text leans each way, in three blocks. The score already carries both things
  // that would make a reader care — it is positive minus negative, so it only gets large when the
  // model is both polarised and sure — which is why one threshold is enough and a separate
  // confidence cut would be redundant.
  //
  // Deliberately discrete while the wash and the ruler stay continuous: this answers "is there
  // anything here", they answer "where, and how strongly". A continuous bar was a second encoding
  // of the same detail and left the question unanswered. It is computed from the same per-segment
  // data as the ruler, so the two can never disagree. Classifying the whole text's mean embedding
  // instead would answer a different question and can contradict the map.
  valenceStrip() {
    const segs = this.model.segments
    const total = segs.reduce((a, s) => a + (s.end - s.start), 0)
    if (!segs.length || !total) return null
    const shareOf = (f: (score: number) => boolean) =>
      segs.filter(s => f(s.score)).reduce((a, s) => a + (s.end - s.start), 0) / total
    const parts = [
      { key: 'negative', label: 'leans negative', share: shareOf(v => v <= -HIGHLIGHT) },
      { key: 'neutral', label: 'no clear lean', share: shareOf(v => Math.abs(v) < HIGHLIGHT) },
      { key: 'positive', label: 'leans positive', share: shareOf(v => v >= HIGHLIGHT) },
    ]
    return div({ class: 'strip' },
      div({ class: 'strip-bar' }, parts.map(p => div({
        class: `strip-seg ${p.key}`,
        style: { width: `${(p.share * 100).toFixed(2)}%` },
      }))),
      div({ class: 'strip-labels' }, parts.map(p =>
        span({ class: `strip-label ${p.key}` }, `${p.label} ${Math.round(p.share * 100)}%`))),
    )
  }

  about() {
    return div({ class: 'about' },
      p('It reads for meaning rather than for words. That comes from MiniLM-L6, a six-layer transformer trained on more than a billion sentence pairs. Then we taught it sentiment directly, on sentences people had marked positive or negative, which is where it learns that a negative word does not always make a sentence negative. That is why "not bad at all" comes out as praise, where counting words would read it as a complaint.'),
      p('Judging that meaning is a separate and much smaller job. Twenty three million values do the reading; barely a thousand do the deciding. Both were settled before you opened this page, so nothing here is learning from what you paste, and the same passage reads the same way every time.'),
      p('To fit a network that size into a browser it is quantised to four bits a value, which takes the download from 90 MB to 13. It then runs on your own graphics card, and nothing you type is sent anywhere.'),
      h2('Where it goes wrong'),
      p({ class: 'about-note' }, 'Every number below was measured on this model, in this page.'),
      ul(
        li(strong('Sarcasm reads as sincere.'), ' "Yeah, great job everyone. Really outstanding work there." comes out 99% positive.'),
        li(strong('Good news can read as a bare fact.'), ' "The vaccine reduced deaths by ninety percent." comes out neutral. It takes the sentence for a plain statement and misses that it is cause for celebration.'),
        li(strong('A negative word inside a noun still weighs.'), ' It handles a negated verb well, so "the people have not failed" reads as hopeful. Negate a noun instead and it flips: "we are stricken by no plague of locusts" comes out strongly negative, because the plague counts for more than the word cancelling it.'),
        li(strong('Implication goes over its head.'), ' When the words agree with the meaning it reads about three quarters of a real speech correctly. When the writer says something good in bleak language, or something damning in mild language, it is close to chance, and that shape is not rare: it was a fifth of the sentences in the address on this page.'),
        li(strong('Trust the shape, not the single line.'), ' When it is wrong it is often confidently wrong: "The years I spent working in that small office were the most demoralising of my life" comes out strongly positive, because it matches the shape of a fond recollection instead of reading the word demoralising. The overall spread is far more reliable than any one highlighted sentence.'),
        li(strong('Every sentence is read alone.'), ' Nothing carries from one sentence to the next, so a remark that only turns bitter in light of what came before is taken at face value. It reads the parts, not the argument they add up to.'),
        li(strong('Grey is not agreement.'), ' The middle of the bar is text with no clear lean, and that covers two different things: writing that genuinely sits on the fence, and writing the model simply could not read. Where the line falls between leaning and not is a threshold someone chose, not something the text decides.'),
        li(strong('English only.'), ' The vocabulary it was built on is English, and the four-bit compression above costs it a little precision against the original model.'),
      ),
      p('The sentiment training draws on the Stanford Sentiment Treebank (Socher et al. 2013), DynaSent, NewsMTSC and ParlaSent, alongside sentences written for this page. The encoder is all-MiniLM-L6-v2 from sentence-transformers, Apache-2.0.'),
    )
  }
}

const root = new Root()
new App({ root, id: 'app' })

tb.onMessage((m: unknown) => {
  if (m === 'paragraphs') return root.model.paragraphProbe()
  // The ruler's bands have no accessible text of their own, so this is how a terminal probe
  // confirms the map was actually built rather than silently empty.
  if (m === 'marks') return {
    windows: root.model.embedTotal,
    classified: root.model.segments.length,
    bands: root.rulerMarks().length,
    // Share of the track each colour occupies. `covered` is now deliberately below 1: only
    // leaning passages are marked, so the remainder is text the model had no lean on.
    share: (() => {
      const b = root.rulerMarks()
      const by: Record<string, number> = { positive: 0, neutral: 0, negative: 0 }
      for (const m of b) {
        const k = (m.class ?? '').split(' ')[0] ?? ''
        by[k] = (by[k] ?? 0) + m.height
      }
      return Object.fromEntries(Object.entries(by).map(([k, v]) => [k, +(v * 100).toFixed(1)]))
    })(),
    covered: +root.rulerMarks().reduce((a, m) => a + m.height, 0).toFixed(4),
    wholeText: root.model.probs
      ? Object.fromEntries(SENTIMENTS.map((s, i) => [s, +(root.model.probs![i]! * 100).toFixed(1)]))
      : null,
    // How many bands are thin enough that the 3px floor in CSS inflates them on screen.
    bandHeightPct: root.rulerMarks().map(m => +(m.height * 100).toFixed(2)).sort((x, y) => x - y),
    // Signed score per segment, character-weighted, for choosing a highlight threshold from the
    // real distribution instead of a guess.
    scores: root.model.segments.map(s => ({ score: +s.score.toFixed(3), chars: s.end - s.start })),
  }
  if (typeof m === 'object' && m !== null && 'classify' in m)
    return root.model.classifyProbe(String((m as { classify: unknown }).classify))
})
```
**styles.css**

```css
:root {
  /* The page is the tint, the cards are the raised surface. Dark mode runs the
     same idea the other way up: near-black page, a step lighter for cards. */
  --bg: #F4F4F5;
  --fg: #1C1C1C;
  --muted: #5A5A5A;
  --panel: #FFFFFF;         /* card surface */
  --raised: #F6F6F7;        /* controls sitting on top of a card */
  --border: #E3E3E6;
  --hairline: #EDEDEF;      /* internal rules inside a card */
  --accent: rgb(58, 125, 232);
  --card-shadow: 0 1px 2px rgba(18, 18, 23, .05), 0 1px 1px rgba(18, 18, 23, .03);
  /* Strength of the wash behind leaning text. Dark mode needs far more of it: the same tint that
     reads clearly on white all but vanishes against a dark panel. */
  --wash-mix: 17%;
  /* How tall a card may grow. Shared so the loading panel and the composer that replaces it have
     one footprint and nothing resizes underfoot at the moment it goes ready. */
  --pane-max: 52dvh;
  /* Sentiment palette: a diverging pair with a deliberately-gray neutral
     midpoint. Validated (dataviz six checks) against both surfaces; identity
     is never color-alone (legend names, percents, center verdict). */
  --positive: #219454;
  --negative: #D14A3C;
  --neutral: #5C5C5C;
}

html[data-theme="dark"] {
  --bg: #161616;
  --fg: #E8E8E8;
  --muted: #979797;
  --panel: #1E1E1E;
  --raised: #2B2B2B;
  --border: #343434;
  --hairline: #2C2C2C;
  --accent: rgb(122, 162, 250);
  --card-shadow: 0 1px 2px rgba(0, 0, 0, .3);
  --wash-mix: 38%;
  --positive: #2FA468;
  --negative: #E26350;
  --neutral: #676767;
}

*, *::before, *::after { box-sizing: border-box; }

html { background: var(--bg); height: 100%; }

body {
  max-width: 920px;
  margin: 0 auto;
  /* Exactly one viewport, with the vertical space as padding rather than margin:
     body margins collapse through to the root, so they are not inside the height
     they appear to be inside, which is what was leaving a permanent scrollbar.
     The page itself never scrolls now; whichever panel is on screen scrolls
     inside itself. dvh rather than vh so mobile chrome can't push the foot off. */
  padding: 1.5rem 1.25rem;
  height: 100dvh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--fg);
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  font-size: 15px;
  line-height: 1.6;
}

h1 { font-size: 1.5rem; font-weight: 650; line-height: 1.2; margin: 0; letter-spacing: -0.01em; }

/* The chain that carries the height down: every link grows, and min-height: 0
   lets them shrink below content size on a short window instead of overflowing. */
#app, .app, .analyzer { flex: 1; display: flex; flex-direction: column; min-height: 0; }

.header { margin-bottom: 1.25rem; }
.tagline { margin: .25rem 0 0; color: var(--muted); font-size: .95rem; }

.tabs { display: flex; gap: 1.25rem; border-bottom: 1px solid var(--border); margin-bottom: 1.5rem; }
.tab {
  font: inherit; font-size: .9rem; font-weight: 550; background: none; border: none; cursor: pointer;
  color: var(--muted); padding: .5rem .1rem .6rem; border-bottom: 2px solid transparent;
  margin-bottom: -1px; transition: color .12s, border-color .12s;
}
.tab:hover { color: var(--fg); }
.tab.active { color: var(--fg); border-bottom-color: var(--accent); }

.composer {
  border: 1px solid var(--border);
  background: var(--panel);
  /* Square: the ruler runs the full height of the pane, and a corner radius clips its ends. */
  border-radius: 0;
  overflow: hidden;
  box-shadow: var(--card-shadow);
  transition: border-color .15s;
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
  /* Grows with the window, but never so far that the bars below it fall off
     the fold: the readout needs its own room on every screen size. */
  max-height: var(--pane-max);
}
.composer:focus-within { border-color: color-mix(in srgb, var(--fg) 30%, var(--border)); }

/* Same card as the composer, so nothing shifts underfoot when it goes ready. */
.loading {
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 1rem; padding: 3rem 1.5rem; text-align: center;
  background: var(--panel); border: 1px solid var(--border); border-radius: 0;
  box-shadow: var(--card-shadow);
  flex: 1;
  max-height: var(--pane-max);      /* the composer's cap exactly: no resize when it goes ready */
}
.loading-lead { margin: 0; color: var(--fg); font-size: 1.05rem; line-height: 1.5; max-width: 32rem; }

/* Centred in the loading card, so it tracks the lead paragraph's column. */
.progress { width: 100%; max-width: 32rem; display: flex; flex-direction: column; gap: .55rem; }
/* In the readout it holds the slot the valence strip is about to take — same
   width, height and radius, so the result resolves in place instead of
   swapping one shape for another. */
.progress.result { max-width: none; gap: .6rem; }
.progress.result .progress-track { height: 12px; }
.progress-track {
  height: 6px; overflow: hidden;
  background: color-mix(in srgb, var(--fg) 10%, transparent);
}
.progress-fill {
  height: 100%;
  background-color: var(--accent);
  /* A slow sheen travelling the filled span: the compile phase can't report a
     fraction, and a bar that holds still there reads as hung. */
  background-image: linear-gradient(90deg, transparent, rgba(255, 255, 255, .38), transparent);
  background-size: 45% 100%;
  background-repeat: no-repeat;
  animation: sheen 1.6s linear infinite;
  transition: width .35s ease;
}
@keyframes sheen { from { background-position: -60% 0; } to { background-position: 160% 0; } }
.progress-row { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; font-size: .85rem; color: var(--muted); }
.progress-step { text-align: left; }
.progress-pct { font-variant-numeric: tabular-nums; }

@media (prefers-reduced-motion: reduce) {
  .progress-fill { animation: none; background-image: none; }
}

.text-input {
  width: 100%;
  flex: 1;
  min-height: 120px;                /* the floor on a short window */
  font: inherit;
  resize: none;                     /* it already tracks the window */
  overflow-y: auto;
  padding: 1rem 1.6rem .5rem 1.1rem;   /* right side is the ruler's channel */
  border: none;
  border-radius: 0;
  background: transparent;
  color: var(--fg);
  line-height: 1.5;
  caret-color: var(--accent);
}
/* The wash layer. Every property that decides where a glyph lands must match .text-input
   exactly — font, size, line-height, padding, wrapping, width — or the colour drifts off the
   words it belongs to. Transparent text rather than no text: the glyphs still have to be laid
   out here, they just aren't the ones you see. */
.text-mirror {
  position: absolute; inset: 0;
  overflow: hidden;
  pointer-events: none;
  z-index: 0;
  font: inherit;
  line-height: 1.5;
  padding: 1rem 1.6rem .5rem 1.1rem;
  white-space: pre-wrap;
  overflow-wrap: break-word;
  color: transparent;
}
/* One strength, two colours, and nothing at all where the text doesn't lean. */
.text-mirror .wash { border-radius: 2px; }
.text-mirror .wash.positive { background: color-mix(in srgb, var(--positive) var(--wash-mix), transparent); }
.text-mirror .wash.negative { background: color-mix(in srgb, var(--negative) var(--wash-mix), transparent); }
.text-input { position: relative; z-index: 1; }
.text-input:focus { outline: none; }
.text-input::placeholder { color: var(--muted); opacity: .7; }

.composer-foot {
  display: flex; align-items: center; justify-content: space-between;
  padding: .55rem .6rem .55rem 1.1rem;
  border-top: 1px solid var(--hairline);
}

/* The overview ruler, copied alongside overviewRuler.ts. .oruler-host is applied by the widget at
   mount, never statically, so the native bar only disappears once its replacement has painted: a
   failure before then leaves an ordinary scrollable pane rather than one with no scroll affordance
   at all. Both hiding routes are needed — the standard property covers Gecko, the pseudo WebKit. */
.oruler-host { scrollbar-width: none; }
.oruler-host::-webkit-scrollbar { width: 0; height: 0; }
.oruler { position: absolute; inset-block: 0; width: 6px; z-index: 5; cursor: default; touch-action: none; }
.oruler-mark { position: absolute; left: 0; right: 0; min-height: 3px; border-radius: 1px; pointer-events: none; }
/* Wider than the track and above the marks, so what's on screen reads as a thumb laid over the map. */
.oruler-win {
  position: absolute; left: -3px; right: -3px; z-index: 1; min-height: 6px; border-radius: 3px;
  pointer-events: none; background: color-mix(in srgb, var(--fg) 28%, transparent);
}
.oruler:hover .oruler-win { background: color-mix(in srgb, var(--fg) 45%, transparent); }
/* A finger needs a target a 6px track can't give; the map is worth more widened than dropped. */
@media (pointer: coarse) {
  .oruler { width: 14px; }
  .oruler-win { left: -2px; right: -2px; }
}
/* Forced colours drop our tints — the window would vanish outright, and the marks' colour IS the
   information, so it keeps its own palette rather than collapsing to one system colour. */
@media (forced-colors: active) {
  .oruler-win { background: transparent; border: 1px solid Highlight; }
  .oruler-mark { forced-color-adjust: none; }
}

/* Its host here: the composer's text pane, mapping sentiment rather than diff lines. */
.text-wrap { position: relative; flex: 1; display: flex; min-height: 0; }
.text-ruler { right: 5px; }
/* The inherited 3px floor exists so a few changed lines in a long diff can't vanish. Here the
   bands tile the whole text and their relative size IS the reading, so a floor is a lie: on this
   text it inflated 16 of 55 bands from 7.3% of the track to 12%, and being absolutely positioned
   they then overlapped their neighbours. A hairline keeps a one-sentence band visible without
   letting it claim room it hasn't earned. */
.text-ruler .oruler-mark { min-height: 1px; }
.text-ruler .oruler-mark.positive { background: var(--positive); opacity: .88; }
.text-ruler .oruler-mark.negative { background: var(--negative); opacity: .88; }
.hint { font-size: .8rem; color: var(--muted); }

.classify-btn {
  font: inherit;
  font-size: .875rem;
  font-weight: 550;
  height: 32px;
  padding: 0 .95rem;
  border: 1px solid var(--border);
  border-radius: 7px;
  background: var(--raised);
  color: var(--fg);
  cursor: pointer;
  white-space: nowrap;
  box-shadow: 0 1px 1px rgba(0, 0, 0, .03);
  transition: background .12s, border-color .12s;
}
.classify-btn:hover { border-color: color-mix(in srgb, var(--fg) 28%, var(--border)); }
.classify-btn:active { background: color-mix(in srgb, var(--fg) 7%, var(--raised)); box-shadow: none; }
.classify-btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.classify-btn:disabled { opacity: .55; cursor: default; box-shadow: none; }
.classify-btn:disabled:hover { border-color: var(--border); }
/* No blinking caret while read-only: it would promise an edit the pane won't accept. */
.text-input:read-only { caret-color: transparent; }

.progress-tail { display: flex; align-items: center; gap: .55rem; }
.stop-btn {
  display: inline-flex; align-items: center; justify-content: center;
  width: 22px; height: 22px; padding: 0;
  border: 1px solid var(--border); border-radius: 5px;
  background: var(--raised); color: var(--muted);
  cursor: pointer; transition: color .12s, border-color .12s;
}
.stop-btn:hover { color: var(--fg); border-color: color-mix(in srgb, var(--fg) 28%, var(--border)); }
.stop-btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.stop-glyph { width: 8px; height: 8px; background: currentColor; border-radius: 1px; }

.readout {
  display: flex; flex-direction: column; align-items: stretch; gap: .9rem;
  padding: 1.75rem .15rem 0;
}
.readout-wait { display: flex; align-items: center; gap: .6rem; color: var(--muted); }

.strip { display: flex; flex-direction: column; gap: .6rem; }
/* Three blocks with a seam between them, because here the boundaries are real: the gaps say
   these are categories, not a continuum. No min-width — a class with nothing in it should
   disappear rather than claim a sliver it hasn't earned. */
.strip-bar { display: flex; gap: 3px; height: 14px; width: 100%; }
.strip-seg { min-width: 0; height: 100%; transition: width .4s ease; }
.strip-seg.positive { background: var(--positive); }
.strip-seg.negative { background: var(--negative); }
.strip-seg.neutral { background: var(--neutral); opacity: .45; }
.strip-labels { display: flex; justify-content: space-between; gap: 1rem; align-items: baseline; }
.strip-label {
  font-size: .85rem; font-weight: 600; color: var(--muted);
  white-space: nowrap; font-variant-numeric: tabular-nums;
}
.strip-label.positive { color: var(--positive); }
.strip-label.negative { color: var(--negative); }

.about {
  color: var(--fg); line-height: 1.65;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 0;                 /* one card shape across the tabs */
  padding: 1.35rem 1.5rem;
  box-shadow: var(--card-shadow);
  /* Its own scroll area: prose can run past the fold without the whole page
     acquiring a scrollbar. */
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  scrollbar-gutter: stable;
}
.about p { margin: 0 0 .9rem; max-width: 640px; }
.about p:last-child { margin-bottom: 0; }
.about h2 { font-size: 1rem; font-weight: 650; letter-spacing: -0.005em; margin: 1.5rem 0 .35rem; }
.about-note { color: var(--muted); font-size: .875rem; }
/* `.about p` sets no top margin and `.about ul` no bottom one, so a paragraph following the list
   sits flush against the last bullet. Two elements deep, which outranks `.about p`. */
.about ul + p { margin-top: .9rem; }
.about ul { margin: 0; padding-left: 1.15rem; max-width: 640px; display: flex; flex-direction: column; gap: .6rem; }
.about li { line-height: 1.55; }
.about li::marker { color: var(--muted); }
.about strong { font-weight: 640; }

.spinner {
  width: 16px; height: 16px; border: 2px solid var(--border); border-top-color: var(--accent);
  border-radius: 50%; display: inline-block; animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

@media (max-width: 700px) {
  h1 { text-align: center; }
  .tagline { text-align: center; }
}

@media (max-width: 640px) {
  body { padding: 1rem .6rem; }
  .about { padding: 1.1rem 1.1rem; }
  .strip-labels { gap: .4rem; }
  .strip-label { font-size: .75rem; }
}
```
**index.html**

```html
<div id="app"></div>
```
**data.txt**

```txt
I am certain that my fellow Americans expect that on my induction into the Presidency I will address them with a candor and a decision which the present situation of our Nation impels. This is preeminently the time to speak the truth, the whole truth, frankly and boldly. Nor need we shrink from honestly facing conditions in our country today. This great Nation will endure as it has endured, will revive and will prosper. So, first of all, let me assert my firm belief that the only thing we have to fear is fear itself—nameless, unreasoning, unjustified terror which paralyzes needed efforts to convert retreat into advance. In every dark hour of our national life a leadership of frankness and vigor has met with that understanding and support of the people themselves which is essential to victory. I am convinced that you will again give that support to leadership in these critical days.

In such a spirit on my part and on yours we face our common difficulties. They concern, thank God, only material things. Values have shrunken to fantastic levels; taxes have risen; our ability to pay has fallen; government of all kinds is faced by serious curtailment of income; the means of exchange are frozen in the currents of trade; the withered leaves of industrial enterprise lie on every side; farmers find no markets for their produce; the savings of many years in thousands of families are gone.

More important, a host of unemployed citizens face the grim problem of existence, and an equally great number toil with little return. Only a foolish optimist can deny the dark realities of the moment.

Yet our distress comes from no failure of substance. We are stricken by no plague of locusts. Compared with the perils which our forefathers conquered because they believed and were not afraid, we have still much to be thankful for. Nature still offers her bounty and human efforts have multiplied it. Plenty is at our doorstep, but a generous use of it languishes in the very sight of the supply. Primarily this is because the rulers of the exchange of mankind's goods have failed, through their own stubbornness and their own incompetence, have admitted their failure, and abdicated. Practices of the unscrupulous money changers stand indicted in the court of public opinion, rejected by the hearts and minds of men.

True they have tried, but their efforts have been cast in the pattern of an outworn tradition. Faced by failure of credit they have proposed only the lending of more money. Stripped of the lure of profit by which to induce our people to follow their false leadership, they have resorted to exhortations, pleading tearfully for restored confidence. They know only the rules of a generation of self-seekers. They have no vision, and when there is no vision the people perish.

The money changers have fled from their high seats in the temple of our civilization. We may now restore that temple to the ancient truths. The measure of the restoration lies in the extent to which we apply social values more noble than mere monetary profit.

Happiness lies not in the mere possession of money; it lies in the joy of achievement, in the thrill of creative effort. The joy and moral stimulation of work no longer must be forgotten in the mad chase of evanescent profits. These dark days will be worth all they cost us if they teach us that our true destiny is not to be ministered unto but to minister to ourselves and to our fellow men.

Recognition of the falsity of material wealth as the standard of success goes hand in hand with the abandonment of the false belief that public office and high political position are to be valued only by the standards of pride of place and personal profit; and there must be an end to a conduct in banking and in business which too often has given to a sacred trust the likeness of callous and selfish wrongdoing. Small wonder that confidence languishes, for it thrives only on honesty, on honor, on the sacredness of obligations, on faithful protection, on unselfish performance; without them it cannot live.

Restoration calls, however, not for changes in ethics alone. This Nation asks for action, and action now.

Our greatest primary task is to put people to work. This is no unsolvable problem if we face it wisely and courageously. It can be accomplished in part by direct recruiting by the Government itself, treating the task as we would treat the emergency of a war, but at the same time, through this employment, accomplishing greatly needed projects to stimulate and reorganize the use of our natural resources.

Hand in hand with this we must frankly recognize the overbalance of population in our industrial centers and, by engaging on a national scale in a redistribution, endeavor to provide a better use of the land for those best fitted for the land. The task can be helped by definite efforts to raise the values of agricultural products and with this the power to purchase the output of our cities. It can be helped by preventing realistically the tragedy of the growing loss through foreclosure of our small homes and our farms. It can be helped by insistence that the Federal, State, and local governments act forthwith on the demand that their cost be drastically reduced. It can be helped by the unifying of relief activities which today are often scattered, uneconomical, and unequal. It can be helped by national planning for and supervision of all forms of transportation and of communications and other utilities which have a definitely public character. There are many ways in which it can be helped, but it can never be helped merely by talking about it. We must act and act quickly.

Finally, in our progress toward a resumption of work we require two safeguards against a return of the evils of the old order; there must be a strict supervision of all banking and credits and investments; there must be an end to speculation with other people's money, and there must be provision for an adequate but sound currency.

There are the lines of attack. I shall presently urge upon a new Congress in special session detailed measures for their fulfillment, and I shall seek the immediate assistance of the several States.

Through this program of action we address ourselves to putting our own national house in order and making income balance outgo. Our international trade relations, though vastly important, are in point of time and necessity secondary to the establishment of a sound national economy. I favor as a practical policy the putting of first things first. I shall spare no effort to restore world trade by international economic readjustment, but the emergency at home cannot wait on that accomplishment.

The basic thought that guides these specific means of national recovery is not narrowly nationalistic. It is the insistence, as a first consideration, upon the interdependence of the various elements in all parts of the United States—a recognition of the old and permanently important manifestation of the American spirit of the pioneer. It is the way to recovery. It is the immediate way. It is the strongest assurance that the recovery will endure.

In the field of world policy I would dedicate this Nation to the policy of the good neighbor—the neighbor who resolutely respects himself and, because he does so, respects the rights of others— the neighbor who respects his obligations and respects the sanctity of his agreements in and with a world of neighbors.

If I read the temper of our people correctly, we now realize as we have never realized before our interdependence on each other; that we can not merely take but we must give as well; that if we are to go forward, we must move as a trained and loyal army willing to sacrifice for the good of a common discipline, because without such discipline no progress is made, no leadership becomes effective. We are, I know, ready and willing to submit our lives and property to such discipline, because it makes possible a leadership which aims at a larger good. This I propose to offer, pledging that the larger purposes will bind upon us all as a sacred obligation with a unity of duty hitherto evoked only in time of armed strife.

With this pledge taken, I assume unhesitatingly the leadership of this great army of our people dedicated to a disciplined attack upon our common problems.

Action in this image and to this end is feasible under the form of government which we have inherited from our ancestors. Our Constitution is so simple and practical that it is possible always to meet extraordinary needs by changes in emphasis and arrangement without loss of essential form. That is why our constitutional system has proved itself the most superbly enduring political mechanism the modern world has produced. It has met every stress of vast expansion of territory, of foreign wars, of bitter internal strife, of world relations.

It is to be hoped that the normal balance of executive and legislative authority may be wholly adequate to meet the unprecedented task before us. But it may be that an unprecedented demand and need for undelayed action may call for temporary departure from that normal balance of public procedure.

I am prepared under my constitutional duty to recommend the measures that a stricken nation in the midst of a stricken world may require. These measures, or such other measures as the Congress may build out of its experience and wisdom, I shall seek, within my constitutional authority, to bring to speedy adoption.

But in the event that the Congress shall fail to take one of these two courses, and in the event that the national emergency is still critical, I shall not evade the clear course of duty that will then confront me. I shall ask the Congress for the one remaining instrument to meet the crisis—broad Executive power to wage a war against the emergency, as great as the power that would be given to me if we were in fact invaded by a foreign foe.

For the trust reposed in me I will return the courage and the devotion that befit the time. I can do no less.

We face the arduous days that lie before us in the warm courage of the national unity; with the clear consciousness of seeking old and precious moral values; with the clean satisfaction that comes from the stem performance of duty by old and young alike. We aim at the assurance of a rounded and permanent national life.

We do not distrust the future of essential democracy. The people of the United States have not failed. In their need they have registered a mandate that they want direct, vigorous action. They have asked for discipline and direction under leadership. They have made me the present instrument of their wishes. In the spirit of the gift I take it.

In this dedication of a Nation we humbly ask the blessing of God. May He protect each and every one of us. May He guide me in the days to come.
```
**config.json**

```json
{
  "dependencies": {
    "tensorgrad": "^0.4.6",
    "domeleon": "^0.6.3"
  },
  "description": "Analyze the sentiment of any text — reviews, emails, essays — with a neural network in your browser. Private: your data never leaves your device."
}
```
**notes.md**

```md
## The encoder

A 6-layer, 384-wide MiniLM, fine-tuned for sentiment and quantized to 4 bits: the big matrices are
group-64 symmetric int4 with one f32 scale per group, while biases, LayerNorms and the
position/token-type tables stay f32. About 13 MB, loaded from
`https://assets.typebulb.com/weights/minilm-sentiment-v2.q4.{bin,json}` plus
`all-MiniLM-L6-v2.vocab.txt`. It is over the free per-bulb asset caps, so it is referenced at an
absolute URL rather than copied here, which keeps forks working on the free tier.

The assets folder is empty on purpose: the page reads no data files at runtime.

## The head

`Linear(384, 3)` over the features, shipped inside the same checkpoint as `fc.W` and `fc.b` and
trained offline on the same corpus as the encoder. The logit scale it was trained under is folded
into those weights, so the browser evaluates plain `softmax(f @ W + b)` and nothing trains at
runtime.

## Segmentation

`MAXLEN` is 64 tokens and one graph is compiled, so longer text is embedded a segment at a time and
token-weight averaged. That equals a masked token mean over the whole text.

## HIGHLIGHT

The point at which a passage is marked at all. It is derived from the measured score distribution,
as the cut that marks about half the sample speech, and must be re-derived whenever the checkpoint
changes. Above it every mark is one fixed strength: the page says a passage leans, and which way,
and nothing more.

## Sample text

Roosevelt's first inaugural, 1933, in `data.txt`. Public domain, a US federal government work.
It is the whole address rather than an excerpt, so there is no selection to defend, and at 1,876
words it exercises the windowing path the moment the page opens.
```