[feat](trx-frontend-http): box the selected tab instead of underlining it

The desktop strip marked the current page with a 2px underline while the
mobile bottom nav already boxed it, so one navigation model looked like
two.  The box now sits on both: a transparent 1px border on the base
reserves it, so switching pages moves no neighbours, and hover fills a
fainter version of the same shape.  Tools carries it too — that button
is marked active for the destinations the strip hides.

Dropping the mobile rule's border-bottom:none, which only existed to
cancel the old desktop underline, closes the bottom edge its active box
had been missing.  The smoke test checks all four edges.

Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/generated/app.js

@@ -2724,6 +2724,17 @@ if (headerStylePickSelect) {
 function readyText() {
   return lastClientCount !== null ? `Ready · ${lastClientCount} user${lastClientCount !== 1 ? "s" : ""}` : "Ready";
 }
+var HINT_ERROR_RE = /failed|missing|unavailable|unknown|lost|required/i;
+var HINT_BUSY_RE = /initializ|connecting|retrying|scanning|shifting|waiting|sending|switching|toggling|setting|not fully/i;
+function hintState(msg) {
+  if (HINT_ERROR_RE.test(msg)) return "error";
+  if (HINT_BUSY_RE.test(msg) || /[\u2026]$|\.\.\.$/.test(msg)) return "busy";
+  return "ok";
+}
+function setPowerHint(msg) {
+  powerHint.textContent = msg;
+  powerHint.dataset.state = hintState(msg);
+}
 function rigBadgeColor(rigId) {
   const text = (rigId || "rx").toString();
   let hash = 0;
@@ -2837,12 +2848,12 @@ function refreshOperatorLayoutCapabilities() {
   });
 }
 function showHint(msg, duration) {
-  powerHint.textContent = msg;
+  setPowerHint(msg);
   if (hintTimer) clearTimeout(hintTimer);
   if (duration) hintTimer = setTimeout(() => {
-    powerHint.textContent = readyText();
+    setPowerHint(readyText());
   }, duration);
-  if (/failed|missing|unavailable|unknown|lost|required/i.test(msg)) {
+  if (HINT_ERROR_RE.test(msg)) {
     window.trxUi?.notify(msg, { kind: "error" });
   }
 }
@@ -4405,13 +4416,13 @@ function render(update) {
       console.info("Rig initializing:", { manufacturer: manu, model, revision: rev });
       loadingEl.style.display = "";
       if (contentEl) contentEl.style.display = "none";
-      powerHint.textContent = "Initializing rig…";
+      setPowerHint("Initializing rig…");
       setDisabled(true);
       return;
     }
     loadingEl.style.display = "none";
     if (contentEl) contentEl.style.display = "";
-    powerHint.textContent = "Rig not fully initialized yet";
+    setPowerHint("Rig not fully initialized yet");
   } else {
     loadingEl.style.display = "none";
     if (contentEl) contentEl.style.display = "";
@@ -4730,7 +4741,7 @@ function render(update) {
     powerBtn.disabled = true;
     powerBtn.textContent = "Power unavailable";
     powerBtn.setAttribute("aria-pressed", "false");
-    powerHint.textContent = "State unknown";
+    setPowerHint("State unknown");
   }
   if (update.status && update.status.tx && typeof update.status.tx.limit === "number") {
     txLimitInput.value = String(update.status.tx.limit);
@@ -4827,7 +4838,7 @@ function render(update) {
   if (Array.isArray(update.remotes)) {
     applyRigList(typeof update.active_remote === "string" ? update.active_remote : null, update.remotes);
   }
-  powerHint.textContent = readyText();
+  setPowerHint(readyText());
   lastLocked = update.status?.lock === true;
   window.trxUi?.setButtonState(lockBtn, {
     active: lastLocked,
@@ -4905,11 +4916,11 @@ function connect() {
       render(data);
       lastEventAt = Date.now();
       if (data.server_connected === false) {
-        powerHint.textContent = "trx-server connection lost";
+        setPowerHint("trx-server connection lost");
         if (tabMainEl) tabMainEl.classList.add("server-disconnected");
       } else {
         if (tabMainEl) tabMainEl.classList.remove("server-disconnected");
-        if (data.initialized) powerHint.textContent = readyText();
+        if (data.initialized) setPowerHint(readyText());
       }
     } catch (e) {
       console.error("Bad event data", e);
@@ -4932,7 +4943,7 @@ function connect() {
   });
   source.onerror = () => {
     if (source.readyState === EventSource.CLOSED) {
-      powerHint.textContent = "trx-client connection lost, retrying…";
+      setPowerHint("trx-client connection lost, retrying…");
       setConnLostOverlay(true, "trx-client connection lost", "Retrying…", true);
       source.close();
       void pollFreshSnapshot();
@@ -4942,7 +4953,7 @@ function connect() {
   esHeartbeat = setInterval(() => {
     const now = Date.now();
     if (now - lastEventAt > 15e3) {
-      powerHint.textContent = "trx-client connection lost, retrying…";
+      setPowerHint("trx-client connection lost, retrying…");
       setConnLostOverlay(true, "trx-client connection lost", "Retrying…", true);
       source.close();
       void pollFreshSnapshot();

src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html

@@ -1594,10 +1594,13 @@ SPDX-License-Identifier: GPL-2.0-or-later
       </template>
     </div>
     <div class="footer">
-      <div class="copyright">
+      <div class="footer-meta">
-        Built by <a href="https://www.qrzcq.com/call/SP2SJG" target="_blank" rel="noopener">SP2SJG</a> from <a href="https://haxx.space" target="_blank" rel="noopener">haxx.space</a> · <span class="gh-link-wrap"><a class="gh-link" href="https://git.haxx.space/sjg/trx-rs" target="_blank" rel="noopener" aria-label="Open trx-rs source repository"><svg class="gh-link-icon" viewBox="0 0 16 16" aria-hidden="true"><path d="M9.5 3.25a2.25 2.25 0 1 1 3 2.122V6A2.5 2.5 0 0 1 10 8.5H6a1 1 0 0 0-1 1v1.128a2.251 2.251 0 1 1-1.5 0V5.372a2.25 2.25 0 1 1 1.5 0v1.836A2.493 2.493 0 0 1 6 7h4a1 1 0 0 0 1-1v-.628A2.25 2.25 0 0 1 9.5 3.25Zm-6 0a.75.75 0 1 0 1.5 0 .75.75 0 0 0-1.5 0Zm8.25-.75a.75.75 0 1 0 0 1.5.75.75 0 0 0 0-1.5ZM4.25 12a.75.75 0 1 0 0 1.5.75.75 0 0 0 0-1.5Z"></path></svg><span>trx-rs source</span></a></span> — <span id="copyright-year"></span>
+        <span class="copyright">
+          Built by <a href="https://www.qrzcq.com/call/SP2SJG" target="_blank" rel="noopener">SP2SJG</a> from <a href="https://haxx.space" target="_blank" rel="noopener">haxx.space</a> · &copy; <span id="copyright-year"></span>
+        </span>
+        <span class="gh-link-wrap"><a class="gh-link" href="https://git.haxx.space/sjg/trx-rs" target="_blank" rel="noopener" aria-label="Open trx-rs source repository"><svg class="gh-link-icon" viewBox="0 0 16 16" aria-hidden="true"><path d="M9.5 3.25a2.25 2.25 0 1 1 3 2.122V6A2.5 2.5 0 0 1 10 8.5H6a1 1 0 0 0-1 1v1.128a2.251 2.251 0 1 1-1.5 0V5.372a2.25 2.25 0 1 1 1.5 0v1.836A2.493 2.493 0 0 1 6 7h4a1 1 0 0 0 1-1v-.628A2.25 2.25 0 0 1 9.5 3.25Zm-6 0a.75.75 0 1 0 1.5 0 .75.75 0 0 0-1.5 0Zm8.25-.75a.75.75 0 1 0 0 1.5.75.75 0 0 0 0-1.5ZM4.25 12a.75.75 0 1 0 0 1.5.75.75 0 0 0 0-1.5Z"></path></svg><span>trx-rs source</span></a></span>
       </div>
-      <div class="hint" id="power-hint" aria-live="polite">Connecting…</div>
+      <div class="hint" id="power-hint" data-state="busy" aria-live="polite">Connecting…</div>
     </div>
     <div id="conn-lost-overlay" class="decode-history-overlay content-overlay is-hidden" aria-live="assertive" aria-atomic="true">
       <div class="decode-history-overlay-card">

src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css

@@ -18,6 +18,9 @@ SPDX-License-Identifier: GPL-2.0-or-later
   --accent-green: #c24b1a;
   --accent-yellow: #f0ad4e;
   --accent-red: #e55353;
+  /* Healthy/on indicator. Distinct from --accent-green, which this theme
+     family uses as the (orange) brand accent rather than a status colour. */
+  --status-ok: #00d17f;
   --vchan-color: #38bdf8;
   --control-height: 2.6rem;
   --jog-hi: #243a5b;
@@ -107,6 +110,8 @@ SPDX-License-Identifier: GPL-2.0-or-later
   --accent-green: #b04317;
   --accent-yellow: #b57600;
   --accent-red: #cf3f3f;
+  /* Darker on light backgrounds: #00d17f as text/dots is barely legible there. */
+  --status-ok: #0a9d63;
   --jog-hi: #e6edf8;
   --jog-lo: #cdd9eb;
   --jog-shadow: rgba(58, 79, 110, 0.18);
@@ -1545,19 +1550,34 @@ small { color: var(--text-muted); }
   .tab-bar-nav .tab .tab-icon, .tab-bar-nav .tab .tab-more-icon { display: block; }
   .tab-bar-nav .tab { padding: 0.5rem 0.6rem; }
 }
+/* The selected destination is boxed, not underlined — the same treatment the
+   mobile bottom nav already used, so one navigation model reads the same at
+   every width. The transparent border is on the base so switching tabs moves
+   no neighbours. */
 .tab {
   background: transparent;
-  border: none;
+  border: 1px solid transparent;
-  border-bottom: 2px solid transparent;
+  border-radius: var(--radius-md);
-  border-radius: 0;
+  padding: 0.45rem 0.9rem;
-  padding: 0.5rem 0.95rem;
   color: var(--text-muted);
   cursor: pointer;
   font-size: 0.95rem;
   height: auto;
+  transition: color var(--dur-fast) var(--ease-standard),
+              background-color var(--dur-fast) var(--ease-standard),
+              border-color var(--dur-fast) var(--ease-standard);
+}
+.tab.active {
+  border-color: color-mix(in srgb, var(--accent-green) 50%, var(--border-light));
+  background: color-mix(in srgb, var(--accent-green) 12%, transparent);
+  color: var(--accent-text);
+  font-weight: 600;
+}
+.tab:hover:not(.active) {
+  color: var(--text);
+  background: color-mix(in srgb, var(--btn-bg) 55%, transparent);
+  border-color: color-mix(in srgb, var(--border-light) 40%, transparent);
 }
-.tab.active { border-bottom-color: var(--accent-green); color: var(--accent-text); font-weight: 600; }
-.tab:hover:not(.active) { color: var(--text); }
 /* Tab icons — hidden on desktop, shown on mobile bottom nav */
 .tab-icon {
   display: none;
@@ -1575,15 +1595,88 @@ small { color: var(--text-muted); }
 .about-table td { padding: 0.4rem 0.75rem; border-bottom: 1px solid color-mix(in srgb, var(--border) 50%, transparent); font-size: 0.85rem; }
 .about-table tr:last-child td { border-bottom: none; }
 .about-table td:first-child { color: var(--text-muted); width: 40%; }
-.about-status-on { color: #00d17f; }
+.about-status-on { color: var(--status-ok); }
 .about-status-off { color: var(--text-muted); }
 .plugin-item { padding: 0.5rem 0.6rem; border-bottom: 1px solid var(--border); color: var(--text); }
 .plugin-item:last-child { border-bottom: none; }
-.footer { display: flex; justify-content: space-between; align-items: baseline; margin-top: auto; padding-top: 1rem; flex-shrink: 0; }
+/* ── Footer ───────────────────────────────────────────────────────────
+   A hairline rule closes the page the way .tab-bar opens it; the two
+   clusters (attribution + source pill, live status chip) sit on one
+   baseline-free centre line so the pills don't hang off the text. */
+.footer {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  gap: var(--space-4);
+  flex-wrap: wrap;
+  margin-top: auto;
+  padding: var(--space-3) 0 var(--space-1);
+  border-top: 1px solid color-mix(in srgb, var(--border-light) 45%, transparent);
+  flex-shrink: 0;
+}
+.footer-meta {
+  display: flex;
+  align-items: center;
+  gap: var(--space-3);
+  flex-wrap: wrap;
+  min-width: 0;
+}
 .full-row { grid-column: 1 / -1; }
-.copyright { color: var(--text-muted); font-size: 0.75rem; opacity: 0.7; }
+/* No opacity: --text-muted is already the muted step, and stacking the
+   two put the attribution below a readable contrast ratio. */
+.copyright { color: var(--text-muted); font-size: var(--fs-xs); }
 .copyright a { color: var(--accent-text); text-decoration: none; }
 .copyright a:hover { text-decoration: underline; }
+/* Live status: dot + text, colour driven by the data-state app.ts sets. */
+.footer .hint {
+  display: inline-flex;
+  align-items: center;
+  gap: var(--space-2);
+  font-size: var(--fs-xs);
+  color: var(--text-heading);
+  padding: 0.2rem 0.6rem;
+  border-radius: var(--radius-pill);
+  border: 1px solid color-mix(in srgb, var(--border-light) 60%, transparent);
+  background: color-mix(in srgb, var(--btn-bg) 55%, transparent);
+  font-variant-numeric: tabular-nums;
+}
+.footer .hint::before {
+  content: "";
+  width: 0.45rem;
+  height: 0.45rem;
+  flex-shrink: 0;
+  border-radius: 50%;
+  background: var(--text-muted);
+  box-shadow: 0 0 0 0.16rem color-mix(in srgb, var(--text-muted) 22%, transparent);
+  transition: background var(--dur-base) var(--ease-standard),
+              box-shadow var(--dur-base) var(--ease-standard);
+}
+.footer .hint[data-state="ok"]::before {
+  background: var(--status-ok);
+  box-shadow: 0 0 0 0.16rem color-mix(in srgb, var(--status-ok) 24%, transparent);
+}
+.footer .hint[data-state="busy"]::before {
+  background: var(--accent-yellow);
+  box-shadow: 0 0 0 0.16rem color-mix(in srgb, var(--accent-yellow) 24%, transparent);
+}
+.footer .hint[data-state="error"] {
+  color: var(--accent-red);
+  border-color: color-mix(in srgb, var(--accent-red) 45%, var(--border-light));
+}
+.footer .hint[data-state="error"]::before {
+  background: var(--accent-red);
+  box-shadow: 0 0 0 0.16rem color-mix(in srgb, var(--accent-red) 24%, transparent);
+}
+@media (prefers-reduced-motion: no-preference) {
+  .footer .hint[data-state="busy"]::before,
+  .footer .hint[data-state="error"]::before {
+    animation: trx-status-pulse 1.8s var(--ease-standard) infinite;
+  }
+}
+@keyframes trx-status-pulse {
+  0%, 100% { opacity: 1; }
+  50%      { opacity: 0.45; }
+}
 .gh-link-wrap {
   display: inline-flex;
   vertical-align: middle;
@@ -1592,6 +1685,8 @@ small { color: var(--text-muted); }
 .gh-link {
   display: inline-flex;
   align-items: center;
+  text-decoration: none;
+  font-size: var(--fs-xs);
   gap: 0.34rem;
   padding: 0.18rem 0.5rem;
   border-radius: 999px;
@@ -1839,11 +1934,17 @@ small { color: var(--text-muted); }
   font-size: 0.82rem;
   color: var(--text-muted);
 }
+/* Full-bleed: break the map panel out of the centred .card column so the
+   stage spans the whole viewport width. The negative inline margins cancel
+   the card's centring offset plus its side padding, whatever they are. */
 #tab-map {
   display: flex;
   flex-direction: column;
   min-height: 0;
   gap: 0.85rem;
+  width: 100vw;
+  max-width: 100vw;
+  margin-inline: calc(50% - 50vw);
 }
 /* map-loading uses the shared .decode-history-overlay .content-overlay classes */
 #map-stage {
@@ -1851,8 +1952,9 @@ small { color: var(--text-muted); }
   flex: 0 1 auto;
   min-height: 0;
   overflow: hidden;
-  border-radius: 6px;
+  border-radius: 0;
   border: 1px solid color-mix(in srgb, var(--border-light) 78%, transparent);
+  border-inline: 0;
   background:
     linear-gradient(180deg, color-mix(in srgb, var(--card-bg) 86%, transparent), color-mix(in srgb, var(--card-bg) 64%, transparent)),
     color-mix(in srgb, var(--input-bg) 88%, transparent);
@@ -3274,7 +3376,6 @@ body[data-operator-layout="broadcast"] #cw-bar-overlay {
     min-height: 3.2rem;
     padding: 0.35rem 0.1rem 0.3rem;
     border: 1px solid transparent;
-    border-bottom: none;
     border-radius: 0.75rem;
     white-space: nowrap;
     text-align: center;

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.ts

@@ -1332,6 +1332,22 @@ function readyText() {
   return lastClientCount !== null ? `Ready \u00b7 ${lastClientCount} user${lastClientCount !== 1 ? "s" : ""}` : "Ready";
 }
 
+// The footer hint is a status pill whose dot is coloured from data-state,
+// so the text has to be written through setPowerHint rather than assigned.
+const HINT_ERROR_RE = /failed|missing|unavailable|unknown|lost|required/i;
+const HINT_BUSY_RE = /initializ|connecting|retrying|scanning|shifting|waiting|sending|switching|toggling|setting|not fully/i;
+
+function hintState(msg: string): "ok" | "busy" | "error" {
+  if (HINT_ERROR_RE.test(msg)) return "error";
+  if (HINT_BUSY_RE.test(msg) || /[\u2026]$|\.\.\.$/.test(msg)) return "busy";
+  return "ok";
+}
+
+function setPowerHint(msg: string) {
+  powerHint.textContent = msg;
+  powerHint.dataset.state = hintState(msg);
+}
+
 function rigBadgeColor(rigId: string) {
   const text = (rigId || "rx").toString();
   let hash = 0;
@@ -1461,10 +1477,10 @@ function refreshOperatorLayoutCapabilities() {
 }
 
 function showHint(msg: string, duration?: number) {
-  powerHint.textContent = msg;
+  setPowerHint(msg);
   if (hintTimer) clearTimeout(hintTimer);
-  if (duration) hintTimer = setTimeout(() => { powerHint.textContent = readyText(); }, duration);
+  if (duration) hintTimer = setTimeout(() => { setPowerHint(readyText()); }, duration);
-  if (/failed|missing|unavailable|unknown|lost|required/i.test(msg)) {
+  if (HINT_ERROR_RE.test(msg)) {
     window.trxUi?.notify(msg, { kind: "error" });
   }
 }
@@ -3292,13 +3308,13 @@ function render(update: AppUpdate) {
       console.info("Rig initializing:", { manufacturer: manu, model, revision: rev });
       loadingEl.style.display = "";
       if (contentEl) contentEl.style.display = "none";
-      powerHint.textContent = "Initializing rig…";
+      setPowerHint("Initializing rig…");
       setDisabled(true);
       return;
     }
     loadingEl.style.display = "none";
     if (contentEl) contentEl.style.display = "";
-    powerHint.textContent = "Rig not fully initialized yet";
+    setPowerHint("Rig not fully initialized yet");
   } else {
     loadingEl.style.display = "none";
     if (contentEl) contentEl.style.display = "";
@@ -3649,7 +3665,7 @@ function render(update: AppUpdate) {
     powerBtn.disabled = true;
     powerBtn.textContent = "Power unavailable";
     powerBtn.setAttribute("aria-pressed", "false");
-    powerHint.textContent = "State unknown";
+    setPowerHint("State unknown");
   }
 
   if (update.status && update.status.tx && typeof update.status.tx.limit === "number") {
@@ -3760,7 +3776,7 @@ function render(update: AppUpdate) {
   if (Array.isArray(update.remotes)) {
     applyRigList(typeof update.active_remote === "string" ? update.active_remote : null, update.remotes);
   }
-  powerHint.textContent = readyText();
+  setPowerHint(readyText());
   lastLocked = update.status?.lock === true;
   window.trxUi?.setButtonState(lockBtn, {
     active: lastLocked,
@@ -3847,11 +3863,11 @@ function connect() {
       render(data);
       lastEventAt = Date.now();
       if (data.server_connected === false) {
-        powerHint.textContent = "trx-server connection lost";
+        setPowerHint("trx-server connection lost");
         if (tabMainEl) tabMainEl.classList.add("server-disconnected");
       } else {
         if (tabMainEl) tabMainEl.classList.remove("server-disconnected");
-        if (data.initialized) powerHint.textContent = readyText();
+        if (data.initialized) setPowerHint(readyText());
       }
     } catch (e) {
       console.error("Bad event data", e);
@@ -3874,7 +3890,7 @@ function connect() {
   source.onerror = () => {
     // Check if this is an auth error by looking at readyState
     if (source.readyState === EventSource.CLOSED) {
-      powerHint.textContent = "trx-client connection lost, retrying\u2026";
+      setPowerHint("trx-client connection lost, retrying\u2026");
       setConnLostOverlay(true, "trx-client connection lost", "Retrying\u2026", true);
       source.close();
       void pollFreshSnapshot();
@@ -3885,7 +3901,7 @@ function connect() {
   esHeartbeat = setInterval(() => {
     const now = Date.now();
     if (now - lastEventAt > 15000) {
-      powerHint.textContent = "trx-client connection lost, retrying\u2026";
+      setPowerHint("trx-client connection lost, retrying\u2026");
       setConnLostOverlay(true, "trx-client connection lost", "Retrying\u2026", true);
       source.close();
       void pollFreshSnapshot();

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/browser-smoke.mjs

@@ -10,7 +10,7 @@ import { fileURLToPath } from "node:url";
 import { chromium } from "playwright-core";
 
 // page.evaluate callbacks run in the browser, not in this Node process.
-/* global document */
+/* global document, getComputedStyle */
 
 const frontendDir = path.dirname(path.dirname(fileURLToPath(import.meta.url)));
 const webDir = path.resolve(frontendDir, "../assets/web");
@@ -194,6 +194,15 @@ try {
   await page.locator("summary", { hasText: "Audio controls" }).click();
   assert.equal(await page.locator("#rx-audio-btn").count(), 1);
 
+  // The footer status pill colours its dot from data-state, so a hint written
+  // straight to textContent would leave the dot stuck on the previous state.
+  const hint = await page.evaluate(() => {
+    const element = document.getElementById("power-hint");
+    return { state: element.dataset.state, text: element.textContent.trim() };
+  });
+  assert.ok(["ok", "busy", "error"].includes(hint.state), `status pill state is ${hint.state}`);
+  assert.equal(hint.state, "ok", `fixture reports "${hint.text}" but the pill is ${hint.state}`);
+
   const rigPicker = page.locator("#header-rig-switch-select");
   await rigPicker.locator("option").nth(1).waitFor({ state: "attached" });
   await rigPicker.selectOption("rig-b");
@@ -203,6 +212,37 @@ try {
   await page.locator('.tab[data-tab="map"]').click();
   await page.locator("#aprs-map .leaflet-pane").first().waitFor({ state: "attached" });
   assert.equal(new URL(page.url()).pathname, "/map");
+
+  // The selected destination is marked by a box on all four sides, so a rule
+  // that drops one edge (the mobile nav used to lose its bottom border) is a
+  // regression even though the tab still reads as "active".
+  const activeTab = await page.evaluate(() => {
+    const style = getComputedStyle(document.querySelector(".tab-bar-nav .tab.active"));
+    return ["Top", "Right", "Bottom", "Left"].map((side) => ({
+      width: style.getPropertyValue(`border-${side.toLowerCase()}-width`),
+      color: style.getPropertyValue(`border-${side.toLowerCase()}-color`),
+    }));
+  });
+  for (const edge of activeTab) {
+    assert.notEqual(edge.width, "0px", `active tab border: ${JSON.stringify(activeTab)}`);
+    assert.ok(!/rgba\(0, 0, 0, 0\)|transparent/.test(edge.color), `active tab border: ${JSON.stringify(activeTab)}`);
+  }
+
+  // The map is full-bleed: it breaks out of the centred .card column and
+  // reaches both viewport edges, without pushing the page sideways.
+  const stage = await page.evaluate(() => {
+    const rect = document.getElementById("map-stage").getBoundingClientRect();
+    return {
+      left: Math.round(rect.left),
+      right: Math.round(rect.right),
+      viewport: document.documentElement.clientWidth,
+      sideways: document.documentElement.scrollWidth > document.documentElement.clientWidth + 1,
+    };
+  });
+  assert.equal(stage.left, 0, `map stage starts at ${stage.left}px, not the viewport edge`);
+  assert.equal(stage.right, stage.viewport, `map stage ends at ${stage.right}px, not ${stage.viewport}px`);
+  assert.equal(stage.sideways, false, "full-bleed map makes the page scroll sideways");
+
   await page.locator('.tab[data-tab="main"]').click();
   assert.equal(new URL(page.url()).pathname, "/");