docs: changelog 2026-07-07 專案整理（階段一／二）＋ index 三分類分層／avoid 七源／demo／19.7em

新增 changelog 2026-07-07「專案整理」條目（架構一致性：透明判定單一真相源＋跨透明邊界避頭尾＋avoid 排除歸一；確認缺陷修復＋清理；復驗後 lineedge 非缺陷／五處幂等不做之定性；文檔重整）＋md-twin 同步。 index 同步：三分類「共用同一判定」改分層表述（isTransparent 為邏輯流單一真相源＋未知行內採嚴格白名單邊界；canSplit／lineedge 為獨立層）、透明列標「未列＝邊界」、avoid 改七源＋isAvoided 組合入口＋skipTags 不含 code/kbd；修 19.5em→19.7em（與 main 一致）；目視驗證補 demo/resize-check 與 demo/showcase 引用。changelog／index HTML 經 build.sh 重建。
2026-07-07 21:21:52 +08:00
parent f75382c9b5
commit 648605ac53
4 changed files with 370 additions and 106 deletions
@@ -1,4 +1,4 @@
-<!-- built with theme=dracula, mode=report, at=2026-06-13T07:41:09Z -->
+<!-- built with theme=dracula, mode=report, at=2026-07-07T13:21:19Z -->
 <!DOCTYPE html>
 <html lang="zh-Hant">
 <head>
@@ -706,6 +706,14 @@ hr.line
 }
 hr.line::before { content: none; }

+.lede
+{
+    /* 首字下沉為 float，本段行數不足以填滿下沉字高度時，浮標會探出段底，
+       令次段首數行繞排、向右擠貼下沉字。將本段下沿托至下沉字下沿（高度＝
+       4.2em × line-height 0.85 ＋ 頂距 8px，與下方 ::first-letter 同步），
+       使次段恆起於下沉字之下。本段自然行高足夠時 min-height 不生效，無副作用。 */
+    min-height: calc(4.2em * 0.85 + 8px);
+}
 .lede::first-letter
 {
    font-family: var(--font-serif);
@@ -2323,9 +2331,10 @@ main > *:nth-child(n+6)            { animation-delay: 0.46s; }


 /* ---------- Mode: report — Print / PDF ----------
-   Dynamic single-page PDF: runtime.js setupDynamicPrintPage() measures
-   content height before print and injects @page sized to fit. Slides
-   mode uses per-slide pagination (page-break-after: always) instead. */
+   Dynamic single-page PDF: report/behavior.js setupDynamicPrintPage()
+   measures the printed height (off-screen iframe at the print column width)
+   and injects @page sized to fit. Slides mode uses per-slide pagination
+   (page-break-after: always) instead. */

 /* ---------- Print ---------- */
 /* ---------- Print / PDF export ----------
@@ -2357,9 +2366,9 @@ main > *:nth-child(n+6)            { animation-delay: 0.46s; }
@page
 {
    /* A4 fallback. Real page size is set dynamically at runtime by
-       `setupDynamicPrintPage()` in runtime.js — it measures the rendered
-       height before print and injects a fresh `@page` rule sized to fit
-       content exactly.
+       `setupDynamicPrintPage()` in report/behavior.js — it measures the
+       printed height (off-screen iframe at the print column width) and
+       injects a fresh `@page` rule sized to fit content exactly.

       Margin: 0 here. The real margin lives in `body` padding (see the
       @media print rule below), which the user's print dialog cannot
@@ -2609,7 +2618,7 @@ createJuzhen({ lang: { default: "zh-Hant" } }).render(document.querySelector("ma
 <tr><td><code>margin</code>（後備）</td><td><code>jiya: { halfWidth: "margin" }</code></td><td><code>width:0.5em</code> ＋字身依墨色偏側溢出定位（以 CSS 重現 halt）</td><td>字型<strong>缺</strong> <code>halt</code>（多數系統字型、GBK 老字型如方正書宋 GBK、PingFang）</td></tr>
 </tbody>
 </table>
-<div class="callout warn"><span class="label">為何需要後備</span> <code>halt</code> 缺席時開明式擠壓「完全無效」（標點仍佔全形）。實測<strong>方正書宋 GBK 僅含 <code>vert</code>、無 <code>halt</code></strong> → halt 模式不擠；切 <code>margin</code> 後備後（開明式 zh-Hans），同句行寬 <code>24.0em → 19.5em</code>、單一句內點號 <code>1.0em → 0.5em</code>，半形生效。</div>
+<div class="callout warn"><span class="label">為何需要後備</span> <code>halt</code> 缺席時開明式擠壓「完全無效」（標點仍佔全形）。實測<strong>方正書宋 GBK 僅含 <code>vert</code>、無 <code>halt</code></strong> → halt 模式不擠；切 <code>margin</code> 後備後（開明式 zh-Hans），同句行寬 <code>24.0em → 19.7em</code>、單一句內點號 <code>1.0em → 0.5em</code>，半形生效。</div>
 <div class="callout"><span class="label">句末標點與連續挤压</span> 句末點號為 <code>。．！？</code>——含<strong>全角句點 <code>．</code></strong>（U+FF0E，異於表意句號 <code>。</code> U+3002，Noto CJK 有 <code>halt</code>）；全角式與開明式句末皆<strong>保持全角 1em</strong>，banjiao 挤半。<strong>連續標點</strong>對每一標點獨立判斷——若其有空白之側緊鄰另一標點即收半形：故 <code>，「</code> <strong>全角式與開明式皆 1em</strong>、<code>。」</code> <strong>全角式 1.5em／開明式 1em</strong>；並透明穿越 <code>strong</code>／<code>em</code> 等行內邊界。<strong>句界例外</strong>：句末點號接開類（<code>。「</code>／<code>？「</code>）為句界，保留句末點號右側空白、僅收開類左側 → 全角式與開明式皆 <strong>1.5em</strong>（對稱於 <code>。」</code>）；例外僅限句末點號＋開類，句內點號 <code>，「</code> 與雙括號 <code>」「</code>／<code>》《</code> 仍兩側皆收 1em。半角式句末點號由 baseline 已半形，故仍 1em（不回歸全寬）。</div>

 <h3>激活與粒度</h3>
@@ -2664,16 +2673,16 @@ createJuzhen({ lang: { default: "zh-Hant" } }).render(document.querySelector("ma
 </ol>

 <h2>行內元素三分類：透明／隔離／整體</h2>
-<p>行內元素對排版有且僅有三種口徑，<strong>所有遍歷原語共用同一判定</strong>（中西間隙、擠壓相鄰、禁則綁定、垂懸字、克隆切分皆一致）；判定<strong>以元素為準、非標籤名</strong>——KaTeX 全樹皆 <code>&lt;span&gt;</code>，但 <code>.katex</code> 命中 <code>pillSelector</code> 即為整體邊界。</p>
+<p>行內元素對排版有且僅有三種口徑。<strong>邏輯文本流之遍歷原語共用單一判定</strong> <code>isTransparent</code>（中西間隙、擠壓相鄰、禁則綁定、垂懸字）；<strong>未在 <code>styleInlines</code> 之未知行內標籤（自訂元素等）採嚴格白名單、一律當邊界</strong>，透明須顯式登記。判定<strong>以元素為準、非標籤名</strong>——KaTeX 全樹皆 <code>&lt;span&gt;</code>，但 <code>.katex</code> 命中 <code>pillSelector</code> 即為整體邊界。結構克隆切分 <code>canSplit</code>、行端物理版面 <code>lineedge</code> 為正當之獨立層（邊界各異，見架構）。</p>
 <table>
 <thead><tr><th>分類</th><th>選擇器</th><th>邊界</th><th>內部</th><th>典型</th></tr></thead>
 <tbody>
-<tr><td><strong>透明</strong></td><td><code>styleInlines</code></td><td>穿越——間隙／相鄰／run 皆延續</td><td>照常處理；禁則可<strong>克隆切分</strong>（最小綁定）</td><td><code>strong</code>／<code>em</code>／<code>a</code>／<code>span</code></td></tr>
+<tr><td><strong>透明</strong></td><td><code>styleInlines</code>（<strong>未列之行內標籤＝邊界</strong>）</td><td>穿越——間隙／相鄰／run 皆延續</td><td>照常處理；禁則可<strong>克隆切分</strong>（最小綁定）</td><td><code>strong</code>／<code>em</code>／<code>a</code>／<code>span</code></td></tr>
 <tr><td><strong>隔離</strong></td><td><code>isolateSelector</code>（預設 <code>"mark"</code>；<code>""</code> 停用）</td><td>斷 run／斷相鄰／不可切分；<strong>兩端</strong>補 <code>jz-hws</code> 間隙</td><td><strong>照常處理</strong>（自成脈絡）</td><td>帶背景色之 <code>&lt;mark&gt;</code>、badge 類</td></tr>
 <tr><td><strong>整體</strong></td><td><code>pillSelector</code>（預設 <code>"code, kbd"</code>）</td><td>同隔離</td><td><strong>完全不可見</strong>——不 charify、不插間隙、不切分、不下潛</td><td><code>code</code>／<code>kbd</code>、行內公式 <code>.katex</code>、引用標 <code>.cite-ref</code></td></tr>
 </tbody>
 </table>
-<p>禁則遇 pill（<code>…$公式$，</code>）：整個 pill 作為原子鄰字單位<strong>整體綁入</strong> <code>jz-jinze</code>（公式本不可斷，無額外代價）；隔離元素同樣整綁（切分背景盒有可見接縫）。<code>scope.avoid</code>／<code>skipAttribute</code>／<code>data-jz-skip</code> 以<strong>自身</strong>判定：命中元素自身即邊界、內外皆不處理。</p>
+<p>禁則遇 pill（<code>…$公式$，</code>）：整個 pill 作為原子鄰字單位<strong>整體綁入</strong> <code>jz-jinze</code>（公式本不可斷，無額外代價）；隔離元素同樣整綁（切分背景盒有可見接縫）。<strong>avoid 七源</strong>（<code>isSkipped</code>／<code>skipTags</code>／SVG／<code>contentEditable</code>／<code>data-jz-skip</code>／<code>skipAttribute</code>／<code>scope.avoid</code>）以<strong>自身</strong>判定、命中即邊界；一次性檢查用組合入口 <code>isAvoided</code>（自身或祖先）。<strong><code>skipTags</code> 預設不含 <code>code</code>／<code>kbd</code></strong>——二者由 <code>pillSelector</code> 以 pill 涵蓋（三分類互斥）。</p>
 <div class="callout"><span class="label">建議</span> 行內公式／夾注引用等獨立行內單位宜列為 pill：<code>pillSelector: "code, kbd, .katex, .cite-ref"</code>——兩側補隙、吸收作者空格、整體綁定，統一處理。</div>

 <h2>分頁器（Paged.js 等）相容：<code>justifyAtoms</code></h2>
@@ -2699,7 +2708,7 @@ createJuzhen({ lang: { default: "zh-Hant" } }).render(document.querySelector("ma
 <p>v1 相容層（<code>createCjkAutospace</code> 導出、IIFE 之全域別名、<code>autospaceClass</code> 選項）<strong>已隨最後一批 v1 消費端遷移完成而移除</strong>。請改用 <code>createJuzhen(options).render(root)</code> v2 API；v1 原始碼保存於 <code>v1-autospace</code> 分支。</p>

 <h2>目視驗證</h2>
-<p><code>demo/index.html</code> 載入 <code>dist/</code> 產物，簡繁並列、可切 <code>justify</code>、附 copy-clean 測試區。<code>demo/fallback.html</code> 以方正書宋 GBK（無 <code>halt</code>）對照 <code>halt</code> 失效 vs <code>margin</code> 後備生效。版面相關結論（justify 單份間距、擠壓視覺量、行端、<code>inline-block</code> 基線）須於 Chrome／Safari／Firefox 三引擎目視核對——jsdom 僅驗證 DOM 結構正確性。</p>
+<p><code>demo/index.html</code> 載入 <code>dist/</code> 產物，簡繁並列、可切 <code>justify</code>、附 copy-clean 測試區。<code>demo/fallback.html</code> 以方正書宋 GBK（無 <code>halt</code>）對照 <code>halt</code> 失效 vs <code>margin</code> 後備生效。<code>demo/resize-check.html</code> 為可拖曳容器檢查頁（驗中西間隙在各寬度恆穩、行末去隙、pill 跨行右隙）。<code>demo/showcase.html</code> 以定寬文本框並列，逐場景演示功能分級與垂懸字。版面相關結論（justify 單份間距、擠壓視覺量、行端、<code>inline-block</code> 基線、間隙隨寬度之穩定性）須於 Chrome／Safari／Firefox 三引擎目視核對——jsdom 僅驗證 DOM 結構正確性。</p>

 </main>

@@ -2774,7 +2783,7 @@ JS 只注入 `jz-*` 結構，所有視覺尺寸在 juzhen.css，缺一不可。

 ## 行內元素三分類

-行內元素對排版三種口徑，所有遍歷原語共用同一判定（以元素為準、非標籤名）：透明（styleInlines——穿越、run 延續、可克隆切分）；隔離（isolateSelector，預設 "mark"——邊界斷 run／斷相鄰／不可切分、兩端補隙，內部照常處理）；整體（pillSelector——內部對一切 pass 不可見，禁則時作為原子鄰字單位整體綁入 jz-jinze）。avoid（scope.avoid／skipAttribute／data-jz-skip）以自身判定，命中即邊界。行內公式／夾注引用宜列為 pill：`pillSelector: "code, kbd, .katex, .cite-ref"`。
+行內元素對排版三種口徑，邏輯文本流之遍歷原語共用單一判定 isTransparent（以元素為準、非標籤名）；未在 styleInlines 之未知行內標籤採嚴格白名單、一律當邊界（透明須顯式登記）：透明（styleInlines——穿越、run 延續、可克隆切分）；隔離（isolateSelector，預設 "mark"——邊界斷 run／斷相鄰／不可切分、兩端補隙，內部照常處理）；整體（pillSelector——內部對一切 pass 不可見，禁則時作為原子鄰字單位整體綁入 jz-jinze）。結構克隆切分 canSplit、行端物理版面 lineedge 為正當之獨立層。avoid 七源（isSkipped／skipTags／SVG／contentEditable／data-jz-skip／skipAttribute／scope.avoid）以自身判定、命中即邊界（一次性用組合 isAvoided）；skipTags 預設不含 code/kbd（由 pill 涵蓋、三分類互斥）。行內公式／夾注引用宜列為 pill：`pillSelector: "code, kbd, .katex, .cite-ref"`。

 ## 分頁器相容

@@ -3652,9 +3661,12 @@ var Juzhen = (() => {
        if (!finder.featureEnabledFor(L, PASS)) {
          return;
        }
-        const lSides = blankSides(bdClassOf(L));
-        const rSides = blankSides(bdClassOf(R));
-        if (lSides.right) {
+        const lClass = bdClassOf(L);
+        const rClass = bdClassOf(R);
+        const lSides = blankSides(lClass);
+        const rSides = blankSides(rClass);
+        const stopBeforeOpen = lClass === "bd-stop" && rClass === "bd-open";
+        if (lSides.right && !stopBeforeOpen) {
          L.classList.add("jz-half");
        }
        if (rSides.left) {
@@ -5092,7 +5104,9 @@ window.__JUZHEN_PUNCT__="quanjiao";window.__JUZHEN_JUSTIFY_ATOMS__=true;window._
               .lede／.marginalia／.references／.appendix……）不命中、維持全功能。最近祖先勝，
               故標題與 chrome 容器一旦命中，其後代（如 .slide-title 內的 .section-name／
               .slide-dot、.title-page 內的作者欄）一併降級。選擇器涵蓋三模式；某模式不存在之
-               class 自然不命中。 */
+               class 自然不命中。**切記只列「非段落 chrome 本身」，切勿納入包裹正文的容器**
+               （如 .deck-stage／.deck／.cols-2）——否則「最近祖先勝」會把整個子樹正文一併降級、
+               喪失禁則／垂懸／長詞（曾誤納 .deck-stage 致 slides 全 deck 正文無禁則、標點落行首）。 */
            level: {
                text: [
                    "h1, h2, h3, h4, h5, h6",                 // 全部標題（含 deck-／section-／slide-／tp-／toc-title）
@@ -5100,7 +5114,7 @@ window.__JUZHEN_PUNCT__="quanjiao";window.__JUZHEN_JUSTIFY_ATOMS__=true;window._
                    ".subtitle, .section-subtitle, .deck-subtitle",   // 副標題
                    ".meta, .timestamp, .actions, .page",     // report chrome
                    ".cover-block, .slide-foot, .toc-list",   // slides 封面／頁尾／目錄條目
-                    ".deck-nav, .deck-counter, .deck-author, .deck-institute, .deck-date, .deck-actions, .deck-stage",
+                    ".deck-nav, .deck-counter, .deck-author, .deck-institute, .deck-date, .deck-actions",
                    ".title-page, .toc-page, .simple-title",  // academic 前置 chrome（含 tp-／st- 欄位）
                ].join(", "),
            },
@@ -5131,9 +5145,10 @@ window.__JUZHEN_PUNCT__="quanjiao";window.__JUZHEN_JUSTIFY_ATOMS__=true;window._
    renderMath();
    wrapFlexTitleText();
    /* 一般模式於 init 立即排版。__JUZHEN_DEFER__（academic 由 build.sh 設）令此處
-       跳過，改由該模式 behavior.js 於 Paged.js preview() 完成後對成品頁呼叫
-       __juzhenRun__——關鍵：Paged.js chunker 對 inline-block 原子量測失準（分頁前
-       排版會致窄欄散架），故先以純文字分頁、再於定版頁上加排版原子。 */
+       跳過，改由該模式 behavior.js 在編號／目錄／正文標記完成後、Paged.js preview()
+       **之前**手動呼叫 __juzhenRun__——使 Paged.js 直接以聚珍後的最終幾何分頁（每頁
+       自然填滿、末行齊滿、無需分頁後斷縫修復）。整頁寬單欄下 chunker 正確量度聚珍
+       inline-block 原子，無散架。 */
    if (!window.__JUZHEN_DEFER__) { runJuzhen(); }

 /* ========== Feature: code-block — behavior =================================
@@ -6042,30 +6057,28 @@ if (!window.__copyDelegated__)


    /* ---------- Dynamic print page sizing ----------
-       Measure the document's rendered height and inject an @page rule
-       sized to fit content exactly. Produces a single-page PDF on "Save
-       as PDF" with no trailing blank space.
+       Measure the document's true printed height and inject an @page rule
+       sized to fit it exactly — a single-page PDF on "Save as PDF" with no
+       trailing blank space and no overflow onto a second page.

-       Page margin: 0. Real margins live in `body` padding (runtime.css
-       @media print). That keeps content width stable regardless of the
-       print dialog's Margins selector — and stable width is what makes
-       the screen-to-print height heuristic reliable.
+       Measurement: an off-screen iframe at the print page width (210mm) with
+       the document's own @media print rules un-gated reproduces the printed
+       layout; its content height is the answer (see measurePrintMm). This is
+       window-independent.

-       Page-height heuristic: with horizontal padding fixed (1cm each
-       side), print rendering height roughly matches screen rendering
-       height. Ratio = 1.0 (was 0.85 — too aggressive an under-estimate;
-       caused tail clipping). The 50mm buffer absorbs the residual
-       variance plus whatever vertical margin a dialog like Chrome's
-       Default might add on top.
+       Earlier this used `documentElement.scrollHeight` × a ratio. That broke
+       because report has NO max-width (content width = 100vw−4em): on a wide
+       window the screen wraps less and measures short, but print always lays
+       out at the fixed 190mm column and wraps more, so the page came out too
+       short and content overflowed. The wider the window, the worse it got.

-       Vertical padding (body padding-top 1.5cm + padding-bottom 1cm =
-       25mm total) is reserved inside the page so the breathing room
-       above the title and below the footer is preserved.
+       Page margin: 0. Real margins live in `body` padding (the @media print
+       rule), so they survive the print dialog's "Margins: None" and stay
+       inside the measured height.

-       Escape hatch: set `window.disablePrintAutoSize = true` (in the
-       DevTools console or before page load) to disable. The injected
-       rule is cleared and printing falls back to the static A4 in
-       runtime.css (multi-page).                                          */
+       Escape hatch: set `window.disablePrintAutoSize = true` (DevTools console
+       or before load) to clear the injected rule and fall back to the static
+       A4 @page in runtime.css (multi-page).                               */
    function setupDynamicPrintPage()
    {
        let styleEl = null;
@@ -6079,25 +6092,95 @@ if (!window.__copyDelegated__)
            }
            return styleEl;
        }
+        /* Collect this document's own `@media print` rules as unconditional
+           CSS, so an off-screen iframe can reproduce the printed-page layout. */
+        function collectPrintCss()
+        {
+            let css = "";
+            Array.from(document.styleSheets).forEach((sheet) =>
+            {
+                let rules;
+                try { rules = sheet.cssRules; }
+                catch (e) { return; }      /* cross-origin sheet — unreadable */
+                Array.from(rules).forEach((rule) =>
+                {
+                    if (rule.type === CSSRule.MEDIA_RULE && /print/i.test(rule.media.mediaText))
+                    {
+                        Array.from(rule.cssRules).forEach((inner) => { css += inner.cssText + "\n"; });
+                    }
+                });
+            });
+            return css;
+        }
+
+        /* Measure the true printed height: clone the already-rendered DOM (KaTeX
+           + juzhen baked in) into a hidden iframe sized to the print page width
+           (210mm) with the print rules un-gated, then read its content height.
+           innerHTML insertion never runs <script>, so the runtime IIFE / KaTeX /
+           juzhen do NOT re-execute. scrollHeight already includes the print
+           `body` padding (the un-gated @media print rule). Resolves to mm.
+
+           Why an iframe and not `documentElement.scrollHeight`: report mode has
+           NO max-width — on-screen content width = 100vw−4em, so screen height
+           tracks the window and diverged from the fixed 190mm print column
+           (wide windows under-sized the page → overflow). The iframe pins the
+           measurement to the real print width, making it window-independent. */
+        function measurePrintMm()
+        {
+            return new Promise((resolve) =>
+            {
+                const iframe = document.createElement("iframe");
+                iframe.setAttribute("aria-hidden", "true");
+                iframe.style.cssText =
+                    "position:fixed;left:-10000px;top:0;width:210mm;height:50px;"
+                    + "border:0;visibility:hidden;";
+                document.body.appendChild(iframe);
+                const idoc = iframe.contentDocument;
+                idoc.open();
+                idoc.write("<!DOCTYPE html><html><head></head><body></body></html>");
+                idoc.close();
+                idoc.documentElement.lang = document.documentElement.lang;
+                idoc.head.innerHTML = document.head.innerHTML;
+                idoc.body.innerHTML = document.body.innerHTML;
+                const ps = idoc.createElement("style");
+                ps.textContent = collectPrintCss();
+                idoc.head.appendChild(ps);
+
+                function done()
+                {
+                    const h  = Math.max(idoc.documentElement.scrollHeight, idoc.body.scrollHeight);
+                    const mm = Math.ceil(h * 25.4 / 96);
+                    iframe.remove();
+                    resolve(mm);
+                }
+                /* Wait for the iframe's fonts (same @font-face, HTTP-cached from
+                   the parent) so glyph metrics match; rAF lets layout settle. */
+                const fontsReady = (idoc.fonts && idoc.fonts.ready) || Promise.resolve();
+                fontsReady.then(() => requestAnimationFrame(() => requestAnimationFrame(done)));
+            });
+        }
+
        function update()
        {
            const el = ensureStyle();
            if (window.disablePrintAutoSize)
            {
-                el.textContent = "";       /* fall back to runtime.css @page */
+                el.textContent = "";       /* fall back to runtime.css static @page */
                return;
            }
-            const PX_TO_MM      = 25.4 / 96;
-            const RATIO         = 1.0;
-            const PAD_V_MM      = 25;      /* body padding-top 15 + padding-bottom 10 */
-            const BUFFER_MM     = 0;       /* absorbs dialog margin + heuristic variance */
-            const screenH       = document.documentElement.scrollHeight;
-            const printContentH = Math.ceil(screenH * PX_TO_MM * RATIO);
-            const pageH         = printContentH + PAD_V_MM + BUFFER_MM;
-            el.textContent      = "@page { size: 210mm " + pageH + "mm; margin: 0; }";
+            measurePrintMm().then((contentMm) =>
+            {
+                if (window.disablePrintAutoSize) { el.textContent = ""; return; }
+                const BUFFER_MM = 10;      /* dialog margin + sub-mm rounding slack */
+                const pageH     = contentMm + BUFFER_MM;
+                el.textContent  = "@page { size: 210mm " + pageH + "mm; margin: 0; }";
+            });
        }
        update();
-        window.addEventListener("resize",      update);
+        /* Print column width is fixed (190mm), so page height no longer depends
+           on the window — no resize re-measure. Re-measure before printing to
+           pick up dynamically expanded/collapsed content (async; the init rule
+           already covers static content for the current print). */
        window.addEventListener("beforeprint", update);
    }