diff --git a/scripts/sitestarlight.py b/scripts/sitestarlight.py
index b146ad0f..60783b53 100644
--- a/scripts/sitestarlight.py
+++ b/scripts/sitestarlight.py
@@ -1,6 +1,6 @@
 """The site as an Astro Starlight project: pages, sidebar and data files.
 
-generate_site.py writes each page body; this module gives it the form
+generate_site.py writes each page body, and this module gives it the form
 Starlight reads. A page's links are written as the docs tree holds them
 (``../systems/sony.md``, MkDocs' convention, the one a Markdown editor
 follows), and the site serves them as addresses under /retrobios/, so
@@ -397,7 +397,12 @@ def finalize_page(
     if boost:
         front["boost"] = boost
     if rel.startswith(CARD_PAGES):
-        front["tableOfContents"] = {"minHeadingLevel": 2, "maxHeadingLevel": 2}
+        sections = len(re.findall(r"^## ", body, re.M))
+        # A page of cards under one or two headings has nothing to list, and
+        # the table of contents watches every block of the page to follow
+        # the reader: 2 x 430 ms of a phone's main thread on 400 cards.
+        front["tableOfContents"] = (
+            {"minHeadingLevel": 2, "maxHeadingLevel": 2} if sections > 2 else False)
     if not search:
         front["pagefind"] = False
     front["head"] = page_head(rel, level, front["title"], browser_title, structured)
diff --git a/website/src/scripts/site.ts b/website/src/scripts/site.ts
index d7e9fd97..68a426dc 100644
--- a/website/src/scripts/site.ts
+++ b/website/src/scripts/site.ts
@@ -131,7 +131,20 @@ const enhanceTables = () => {
 		},
 		{ rootMargin: '400px 0px' },
 	);
-	tables.forEach((table) => observer.observe(table));
+	// Every table is measured once the page is drawn and idle, before anything
+	// is written, so the read finds the layout done instead of forcing it: a
+	// keyboard reaches a scrolling table anywhere on the page, not only near
+	// the screen.
+	const idle = window.requestIdleCallback ?? ((callback: () => void) => setTimeout(callback, 1));
+	const start = () =>
+		idle(() => {
+			// A table in a closed block is not laid out, and measuring it would
+			// lay it out: it is measured when its block opens.
+			markScrollable(tables.filter((table) => table.checkVisibility?.() ?? true));
+			tables.forEach((table) => observer.observe(table));
+		});
+	if (document.readyState === 'complete') start();
+	else addEventListener('load', start, { once: true });
 	let timer = 0;
 	addEventListener('resize', () => {
 		clearTimeout(timer);
diff --git a/website/tools/check_tools.mjs b/website/tools/check_tools.mjs
index 2e843d8b..facb8d79 100644
--- a/website/tools/check_tools.mjs
+++ b/website/tools/check_tools.mjs
@@ -71,6 +71,9 @@ console.log('glossary term:', await term.textContent(), '=', await term.getAttri
 // On a phone, a table whose rows end in a download is one block per row.
 await page.setViewportSize({ width: 390, height: 844 });
 await page.goto(`${base}which-pack/`, { waitUntil: 'networkidle' });
+// Tables are set up as they near the screen.
+await page.locator('table:has(a[href*="/releases/download/"])').first().scrollIntoViewIfNeeded();
+await page.waitForTimeout(300);
 const stacked = await page.locator('table[data-rb-stack]').count();
 const overflow = await page.evaluate(() => document.documentElement.scrollWidth > innerWidth + 1);
 console.log('stacked tables:', stacked, 'page wider than the phone:', overflow);
diff --git a/website/tools/lighthouse.py b/website/tools/lighthouse.py
index 3c8bbfce..e40ea638 100644
--- a/website/tools/lighthouse.py
+++ b/website/tools/lighthouse.py
@@ -42,7 +42,9 @@ def main() -> int:
                 ["npx", "--prefix", str(Path(__file__).resolve().parent.parent), "lighthouse", base + page,
                  "--quiet", "--output=json", f"--output-path={report.resolve()}",
                  "--chrome-flags=--headless=new --no-sandbox",
-                 f"--only-categories={','.join(categories)}"],
+                 f"--only-categories={','.join(categories)}",
+                 # Extra flags for one experiment, space separated.
+                 *os.environ.get("LIGHTHOUSE_FLAGS", "").split()],
                 env=env, cwd=out, check=False, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
             data = json.loads(report.read_text())
             cats, audits = data["categories"], data["audits"]