From 24f781d398e3e33e48a8cf78c7703f74135964e6 Mon Sep 17 00:00:00 2001
From: timmy <timmy@stackchain.ai>
Date: Sun, 16 Aug 2026 15:58:41 +0000
Subject: [PATCH] feat: add mobile Search Preview navigation (Closes #973)

---
 .gitea/workflows/ci.yml                       |   4 +-
 frontend/dashboard.css                        |  31 +++-
 frontend/index.html                           |  19 ++-
 frontend/mobile-search-preview-nav.js         | 130 +++++++++++++++++
 frontend/service-worker.js                    |   1 +
 src/frontend_bundle.py                        |   2 +-
 .../test_mobile_search_preview_navigation.py  |  70 +++++++++
 tests/test_ci_workflow.py                     |   5 +-
 .../test_mobile_search_preview_navigation.py  | 135 ++++++++++++++++++
 tests/test_service_worker.py                  |   1 +
 10 files changed, 388 insertions(+), 10 deletions(-)
 create mode 100644 frontend/mobile-search-preview-nav.js
 create mode 100644 tests/e2e/test_mobile_search_preview_navigation.py
 create mode 100644 tests/test_mobile_search_preview_navigation.py

diff --git a/.gitea/workflows/ci.yml b/.gitea/workflows/ci.yml
index cbdef00..1538fa7 100644
--- a/.gitea/workflows/ci.yml
+++ b/.gitea/workflows/ci.yml
@@ -54,8 +54,8 @@ jobs:
         run: |
           pip install -r requirements-e2e.txt
           python3 -m playwright install --with-deps chromium
-      - name: Exercise mobile offline filing from the release artifact
-        run: python3 -m pytest tests/e2e/test_mobile_offline_issue_release.py -q
+      - name: Exercise mobile offline filing and Search Preview navigation
+        run: python3 -m pytest tests/e2e/test_mobile_offline_issue_release.py tests/e2e/test_mobile_search_preview_navigation.py -q
 
   release-candidate:
     runs-on: ubuntu-latest
diff --git a/frontend/dashboard.css b/frontend/dashboard.css
index c172136..8c48178 100644
--- a/frontend/dashboard.css
+++ b/frontend/dashboard.css
@@ -654,8 +654,10 @@ textarea { resize: vertical; min-height: 120px; }
 .find-work-detail a { display:flex; align-items:center; justify-content:center; border:1px solid #60a5fa; border-radius:10px; font-weight:700; }
 .search-preview { position:fixed; inset:0; z-index:60; display:none; justify-content:flex-end; background:rgba(5,12,21,.72); backdrop-filter:blur(4px); }
 .search-preview.open { display:flex; }
-.search-preview-panel { box-sizing:border-box; width:min(560px,100%); height:100dvh; overflow:auto; display:grid; align-content:start; gap:12px; padding:18px; padding-bottom:calc(18px + env(safe-area-inset-bottom)); background:#0b1526; border-left:1px solid #2a496e; overflow-wrap:anywhere; }
+.search-preview-panel { box-sizing:border-box; width:min(560px,100%); height:100dvh; overflow:auto; overflow-x:hidden; display:grid; align-content:start; gap:12px; padding:18px; padding-bottom:calc(18px + env(safe-area-inset-bottom)); background:#0b1526; border-left:1px solid #2a496e; overflow-wrap:anywhere; }
 .search-preview-header { display:flex; align-items:flex-start; justify-content:space-between; gap:10px; }
+.mobile-search-preview-nav { display:none; }
+.search-preview-overview { display:grid; gap:12px; min-width:0; }
 .search-preview-header button, .search-preview-actions button, .search-preview-actions a { min-height:44px; }
 .search-preview-body { margin:0; white-space:pre-wrap; overflow-wrap:anywhere; }
 .search-preview-conversation { display:grid; gap:8px; padding-top:8px; border-top:1px solid #2a496e; }
@@ -678,6 +680,33 @@ textarea { resize: vertical; min-height: 120px; }
 @media (max-width:420px) {
   .search-preview-primary-actions { grid-template-columns:1fr; }
 }
+@media (max-width:600px) {
+  .search-preview-panel { width:100%; border-left:0; padding:14px; padding-top:max(12px,env(safe-area-inset-top)); }
+  .mobile-search-preview-nav {
+    position:sticky; top:env(safe-area-inset-top); z-index:6;
+    display:grid; grid-template-columns:repeat(4,minmax(0,1fr)); gap:4px;
+    margin-inline:-14px; padding:4px 14px;
+    background:rgba(11,21,38,.98); border-block:1px solid #2a496e;
+  }
+  .mobile-search-preview-nav button {
+    min-width:0; min-height:44px; padding:4px; overflow-wrap:anywhere;
+    border-color:transparent; font-size:12px;
+  }
+  .mobile-search-preview-nav button[aria-current="location"] {
+    border-color:#60a5fa; background:#17365a; color:#fff;
+  }
+  .mobile-search-preview-nav button[aria-disabled="true"] { opacity:.55; }
+  .search-preview-navigation {
+    position:sticky; bottom:0; z-index:5;
+    margin-inline:-6px; padding:6px;
+    padding-bottom:calc(6px + env(safe-area-inset-bottom));
+    background:rgba(11,21,38,.98); border-block:1px solid #2a496e;
+  }
+  #search-preview-overview, #search-preview-conversation,
+  #search-preview-reply-workspace, #search-preview-actions { scroll-margin-top:72px; }
+  #search-preview-actions { position:static; }
+}
+@media (min-width:601px) { .mobile-search-preview-nav { display:none; } }
 .search-preview-actions a { display:flex; align-items:center; justify-content:center; border:1px solid #60a5fa; border-radius:10px; font-weight:700; }
 .markdown-content { min-width:0; max-width:100%; overflow-wrap:anywhere; white-space:normal; }
 .markdown-content > :first-child { margin-top:0; }
diff --git a/frontend/index.html b/frontend/index.html
index b8ace3e..6a1ca0c 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -533,9 +533,17 @@
       </div>
       <button id="close-search-preview" type="button">Back to search</button>
     </div>
-    <div id="search-preview-status" class="small" aria-live="polite">Choose a search result.</div>
-    <div id="search-preview-meta" class="row"></div>
-    <div id="search-preview-body" class="search-preview-body markdown-content"></div>
+    <nav class="mobile-search-preview-nav" aria-label="Search preview sections">
+      <button type="button" data-search-preview-section="overview">Overview</button>
+      <button type="button" data-search-preview-section="conversation">Conversation</button>
+      <button type="button" data-search-preview-section="reply">Reply</button>
+      <button type="button" data-search-preview-section="actions">Act</button>
+    </nav>
+    <section id="search-preview-overview" class="search-preview-overview">
+      <div id="search-preview-status" class="small" aria-live="polite">Choose a search result.</div>
+      <div id="search-preview-meta" class="row"></div>
+      <div id="search-preview-body" class="search-preview-body markdown-content"></div>
+    </section>
     <section id="search-preview-conversation" class="search-preview-conversation" aria-labelledby="search-preview-conversation-title">
       <h2 id="search-preview-conversation-title">Current conversation</h2>
       <div id="search-preview-comments"></div>
@@ -543,7 +551,7 @@
       <button id="retry-search-preview-conversation" type="button" hidden>Retry conversation</button>
       <button id="load-older-search-preview-comments" type="button" hidden>Load older messages</button>
     </section>
-    <section class="search-preview-reply" aria-labelledby="search-preview-reply-title" hidden>
+    <section class="search-preview-reply" id="search-preview-reply-workspace" aria-labelledby="search-preview-reply-title" hidden>
       <h2 id="search-preview-reply-title">Reply</h2>
       <textarea id="search-preview-reply" maxlength="10000" placeholder="Write a reply"></textarea>
       <section class="voice-conversation" id="voice-search-reply" aria-label="Dictate search result reply" hidden>
@@ -589,7 +597,7 @@
         <button id="send-search-preview-reply-next" type="button">Send &amp; next</button>
       </div>
     </section>
-    <div class="search-preview-actions">
+    <div class="search-preview-actions" id="search-preview-actions">
       <nav class="search-preview-navigation" aria-label="Search result navigation" hidden>
         <button id="previous-search-result" type="button">Previous</button>
         <span id="search-preview-position" aria-live="polite"></span>
@@ -1579,6 +1587,7 @@
 <script src="static/mobile-issue-detail-nav.js"></script>
 <script src="static/mobile-update-detail-nav.js"></script>
 <script src="static/mobile-review-detail-nav.js"></script>
+<script src="static/mobile-search-preview-nav.js"></script>
 <script src="static/dashboard.js"></script>
 </body>
 </html>
diff --git a/frontend/mobile-search-preview-nav.js b/frontend/mobile-search-preview-nav.js
new file mode 100644
index 0000000..73d0cc1
--- /dev/null
+++ b/frontend/mobile-search-preview-nav.js
@@ -0,0 +1,130 @@
+function createMobileSearchPreviewNavigation(options) {
+  const buttons = options.buttons || {};
+  const targets = options.targets || {};
+  const focusTargets = options.focusTargets || {};
+  const listeners = new Map();
+  const prefersReducedMotion = options.prefersReducedMotion || (() => false);
+  const targetNames = new Map(Object.entries(targets).map(([name, target]) => [target, name]));
+  let replyAvailable = options.replyAvailable !== false;
+  let observer = null;
+  let navigationLockUntil = 0;
+
+  function select(name) {
+    Object.entries(buttons).forEach(([key, button]) => {
+      if (!button) return;
+      if (key === name) button.setAttribute('aria-current', 'location');
+      else button.removeAttribute('aria-current');
+    });
+  }
+
+  function setReplyAvailable(available) {
+    replyAvailable = Boolean(available);
+    const button = buttons.reply;
+    if (!button) return;
+    if (replyAvailable) button.removeAttribute('aria-disabled');
+    else button.setAttribute('aria-disabled', 'true');
+  }
+
+  function navigate(name) {
+    if (name === 'reply' && !replyAvailable) return false;
+    const target = targets[name];
+    if (!target) return false;
+    target.scrollIntoView({
+      block: 'start',
+      behavior: prefersReducedMotion() ? 'auto' : 'smooth',
+    });
+    navigationLockUntil = Date.now() + 500;
+    select(name);
+    const focusTarget = focusTargets[name] || (name === 'reply' ? target : null);
+    if (focusTarget) focusTarget.focus({preventScroll:true});
+    return true;
+  }
+
+  function reset(available = replyAvailable) {
+    setReplyAvailable(available);
+    select('overview');
+  }
+
+  return {
+    start() {
+      Object.entries(buttons).forEach(([name, button]) => {
+        if (!button || listeners.has(button)) return;
+        const listener = event => {
+          event.preventDefault();
+          navigate(name);
+        };
+        listeners.set(button, listener);
+        button.addEventListener('click', listener);
+      });
+      reset(replyAvailable);
+      const observe = options.observe || ((handler, observedTargets, root) => {
+        if (typeof IntersectionObserver === 'undefined') return null;
+        const instance = new IntersectionObserver(handler, {
+          root,
+          rootMargin: '-20% 0px -60% 0px',
+          threshold: [0, 0.25, 0.5, 0.75, 1],
+        });
+        observedTargets.forEach(target => instance.observe(target));
+        return instance;
+      });
+      observer = observe(entries => {
+        if (Date.now() < navigationLockUntil) return;
+        const visible = entries
+          .filter(entry => entry.isIntersecting && targetNames.has(entry.target))
+          .filter(entry => targetNames.get(entry.target) !== 'reply' || replyAvailable)
+          .sort((left, right) => right.intersectionRatio - left.intersectionRatio)[0];
+        if (visible) select(targetNames.get(visible.target));
+      }, Array.from(targetNames.keys()).filter(Boolean), options.root || null);
+    },
+    stop() {
+      listeners.forEach((listener, button) => button.removeEventListener('click', listener));
+      listeners.clear();
+      if (observer) observer.disconnect();
+      observer = null;
+    },
+    navigate,
+    reset,
+    select,
+    setReplyAvailable,
+  };
+}
+
+function attachMobileSearchPreviewNavigation({document, window}) {
+  const bySection = name => document.querySelector('[data-search-preview-section="' + name + '"]');
+  const preview = document.getElementById('search-preview');
+  const reply = document.getElementById('search-preview-reply-workspace');
+  const navigation = createMobileSearchPreviewNavigation({
+    root:document.querySelector('.search-preview-panel'),
+    buttons:{
+      overview:bySection('overview'),
+      conversation:bySection('conversation'),
+      reply:bySection('reply'),
+      actions:bySection('actions'),
+    },
+    targets:{
+      overview:document.getElementById('search-preview-overview'),
+      conversation:document.getElementById('search-preview-conversation'),
+      reply,
+      actions:document.getElementById('search-preview-actions'),
+    },
+    focusTargets:{reply:document.getElementById('search-preview-reply')},
+    replyAvailable:!reply.hidden,
+    prefersReducedMotion:() => window.matchMedia('(prefers-reduced-motion: reduce)').matches,
+  });
+  navigation.start();
+  new MutationObserver(() => navigation.setReplyAvailable(!reply.hidden)).observe(reply, {
+    attributes:true, attributeFilter:['hidden'],
+  });
+  new MutationObserver(() => {
+    if (preview.classList.contains('open')) navigation.reset(!reply.hidden);
+  }).observe(preview, {attributes:true, attributeFilter:['class']});
+  ['previous-search-result', 'next-search-result'].forEach(id => {
+    document.getElementById(id).addEventListener('click', () => {
+      setTimeout(() => navigation.reset(!reply.hidden), 0);
+    });
+  });
+  return navigation;
+}
+
+if (typeof module !== 'undefined') module.exports = createMobileSearchPreviewNavigation;
+else attachMobileSearchPreviewNavigation({document, window});
diff --git a/frontend/service-worker.js b/frontend/service-worker.js
index e8e9636..e5ba95b 100644
--- a/frontend/service-worker.js
+++ b/frontend/service-worker.js
@@ -80,6 +80,7 @@ const SHELL = [
   BASE + 'static/mobile-issue-detail-nav.js',
   BASE + 'static/mobile-update-detail-nav.js',
   BASE + 'static/mobile-review-detail-nav.js',
+  BASE + 'static/mobile-search-preview-nav.js',
   BASE + 'static/checklist-conflict.js',
   BASE + 'static/voice-transcript-store.js',
   BASE + 'static/voice-issue-capture.js',
diff --git a/src/frontend_bundle.py b/src/frontend_bundle.py
index e724cf7..7445bc1 100644
--- a/src/frontend_bundle.py
+++ b/src/frontend_bundle.py
@@ -31,7 +31,7 @@ FEATURE_SOURCES = {
     "security-center": ("static/security-center.js",),
     "today-timer": (
         "static/voice-transcript-store.js", "static/voice-conversation-capture.js",
-        "static/today-completion.js", "static/work-detail-position.js", "static/work-route.js", "static/commands.js", "static/saved-searches.js", "static/task-overlay-history.js", "static/search-preview.js", "static/search-reply-draft-store.js", "static/conversation-reply-draft-store.js", "static/conversation-photo-drafts.js", "static/search-defer.js", "static/mobile-search-viewport.js", "static/my-work.js", "static/protect-today.js", "static/mobile-task-dock.js", "static/mobile-queue-launcher.js", "static/mobile-start-day.js", "static/update-triage-session.js", "static/update-review-handoff.js", "static/update-triage-launcher.js", "static/update-triage-gesture.js", "static/notification-undo.js", "static/today-timer.js", "static/today-recap.js",
+        "static/today-completion.js", "static/work-detail-position.js", "static/work-route.js", "static/commands.js", "static/saved-searches.js", "static/task-overlay-history.js", "static/search-preview.js", "static/mobile-search-preview-nav.js", "static/search-reply-draft-store.js", "static/conversation-reply-draft-store.js", "static/conversation-photo-drafts.js", "static/search-defer.js", "static/mobile-search-viewport.js", "static/my-work.js", "static/protect-today.js", "static/mobile-task-dock.js", "static/mobile-queue-launcher.js", "static/mobile-start-day.js", "static/update-triage-session.js", "static/update-review-handoff.js", "static/update-triage-launcher.js", "static/update-triage-gesture.js", "static/notification-undo.js", "static/today-timer.js", "static/today-recap.js",
         "static/today-rollover.js", "static/later-work.js", "static/later-picker.js", "static/drafts.js", "static/unfiled-captures.js", "static/unfiled-draft-sync.js",
         "static/assign-and-start.js", "static/filed-claim.js", "static/queue-today.js", "static/create-and-start.js",
         "static/draft-filing-session.js", "static/draft-capacity-dialog.js", "static/work-selection.js",
diff --git a/tests/e2e/test_mobile_search_preview_navigation.py b/tests/e2e/test_mobile_search_preview_navigation.py
new file mode 100644
index 0000000..3710bb7
--- /dev/null
+++ b/tests/e2e/test_mobile_search_preview_navigation.py
@@ -0,0 +1,70 @@
+from __future__ import annotations
+
+import re
+from pathlib import Path
+
+import pytest
+
+pytest.importorskip("playwright.sync_api")
+from playwright.sync_api import expect, sync_playwright
+
+
+ROOT = Path(__file__).resolve().parents[2]
+FRONTEND = ROOT / "frontend"
+
+
+@pytest.mark.parametrize(("width", "height"), [(320, 568), (390, 844)])
+def test_rendered_mobile_search_preview_navigation_preserves_reading_space_and_draft(width, height):
+    html = re.sub(r'<script src="static/[^"]+"></script>', "", (FRONTEND / "index.html").read_text())
+
+    with sync_playwright() as playwright:
+        browser = playwright.chromium.launch()
+        page = browser.new_page(viewport={"width": width, "height": height})
+        page.set_content(html)
+        page.add_style_tag(path=FRONTEND / "dashboard.css")
+        page.locator("#search-preview").evaluate("node => node.classList.add('open')")
+        page.locator("#search-preview-reply-workspace").evaluate("node => node.hidden = false")
+        page.locator(".search-preview-navigation").evaluate("node => node.hidden = false")
+        page.locator("#search-preview-overview").evaluate("node => node.style.minHeight = '500px'")
+        page.locator("#search-preview-conversation").evaluate("node => node.style.minHeight = '500px'")
+        page.locator("#search-preview-reply-workspace").evaluate("node => node.style.minHeight = '500px'")
+        page.locator("#search-preview-actions").evaluate("node => node.style.minHeight = '300px'")
+        page.add_script_tag(path=FRONTEND / "mobile-search-preview-nav.js")
+
+        navigation = page.locator(".mobile-search-preview-nav")
+        expect(navigation).to_be_visible()
+        buttons = navigation.locator("button")
+        assert buttons.count() == 4
+        for button in buttons.all():
+            bounds = button.bounding_box()
+            assert bounds and bounds["height"] >= 44
+        assert page.evaluate("document.documentElement.scrollWidth <= window.innerWidth")
+        assert page.locator(".search-preview-panel").evaluate("node => node.scrollWidth <= node.clientWidth")
+
+        page.locator("#search-preview-reply").fill("Keep this reply while navigating")
+        navigation.locator('[data-search-preview-section="conversation"]').click()
+        expect(navigation.locator('[data-search-preview-section="conversation"]')).to_have_attribute(
+            "aria-current", "location"
+        )
+        navigation.locator('[data-search-preview-section="reply"]').click()
+        expect(page.locator("#search-preview-reply")).to_be_focused()
+        assert page.locator("#search-preview-reply").input_value() == "Keep this reply while navigating"
+        navigation.locator('[data-search-preview-section="actions"]').click()
+        expect(navigation.locator('[data-search-preview-section="actions"]')).to_have_attribute(
+            "aria-current", "location"
+        )
+
+        continuation = page.locator(".search-preview-navigation")
+        assert continuation.evaluate("node => getComputedStyle(node).position") == "sticky"
+        assert continuation.evaluate("node => getComputedStyle(node).bottom") == "0px"
+        assert page.locator("#search-preview-actions").evaluate("node => getComputedStyle(node).position") == "static"
+
+        page.locator("#next-search-result").click()
+        expect(navigation.locator('[data-search-preview-section="overview"]')).to_have_attribute(
+            "aria-current", "location"
+        )
+        assert page.locator("#search-preview-reply").input_value() == "Keep this reply while navigating"
+
+        page.set_viewport_size({"width": 800, "height": 700})
+        expect(navigation).to_be_hidden()
+        browser.close()
diff --git a/tests/test_ci_workflow.py b/tests/test_ci_workflow.py
index d61a73f..f304dad 100644
--- a/tests/test_ci_workflow.py
+++ b/tests/test_ci_workflow.py
@@ -38,5 +38,8 @@ def test_release_promotion_waits_for_artifact_mobile_offline_journey():
     assert "pip install -r requirements-e2e.txt" in browser
     assert "python3 -m playwright install --with-deps chromium" in browser
     assert 'STACKCHAIN_RUN_RELEASE_E2E: "1"' in browser
-    assert "python3 -m pytest tests/e2e/test_mobile_offline_issue_release.py -q" in browser
+    assert (
+        "python3 -m pytest tests/e2e/test_mobile_offline_issue_release.py "
+        "tests/e2e/test_mobile_search_preview_navigation.py -q"
+    ) in browser
     assert "needs: [lint, build-release, browser-journey]" in release
diff --git a/tests/test_mobile_search_preview_navigation.py b/tests/test_mobile_search_preview_navigation.py
new file mode 100644
index 0000000..1b06690
--- /dev/null
+++ b/tests/test_mobile_search_preview_navigation.py
@@ -0,0 +1,135 @@
+import json
+import subprocess
+from pathlib import Path
+
+
+CONTROLLER = Path(__file__).resolve().parents[1] / "frontend" / "mobile-search-preview-nav.js"
+FRONTEND = CONTROLLER.parent
+
+
+def run_navigation(scenario: str) -> dict:
+    script = f"""
+const createNavigation = require({json.dumps(str(CONTROLLER))});
+class FakeElement {{
+  constructor(name) {{
+    this.name=name; this.listeners={{}}; this.attributes={{}}; this.scrolls=[];
+    this.focuses=0; this.hidden=false;
+  }}
+  addEventListener(name, callback) {{ this.listeners[name]=callback; }}
+  removeEventListener(name) {{ delete this.listeners[name]; }}
+  click() {{ this.listeners.click?.({{preventDefault() {{}}}}); }}
+  setAttribute(name,value) {{ this.attributes[name]=value; }}
+  removeAttribute(name) {{ delete this.attributes[name]; }}
+  scrollIntoView(options) {{ this.scrolls.push(options); }}
+  focus(options) {{ this.focuses += 1; this.focusOptions=options; }}
+}}
+{scenario}
+"""
+    result = subprocess.run(["node", "-e", script], capture_output=True, text=True)
+    assert result.returncode == 0, result.stderr
+    return json.loads(result.stdout)
+
+
+def test_mobile_search_preview_navigation_completes_the_workflow_and_gates_reply():
+    result = run_navigation("""
+const names=['overview','conversation','reply','actions'];
+const buttons=Object.fromEntries(names.map(name=>[name,new FakeElement(name)]));
+const targets=Object.fromEntries(names.map(name=>[name,new FakeElement(name)]));
+const navigation=createNavigation({buttons,targets,prefersReducedMotion:()=>true});
+navigation.start();
+navigation.setReplyAvailable(false);
+buttons.reply.click();
+const unavailableScrolls=targets.reply.scrolls.length;
+navigation.setReplyAvailable(true);
+buttons.conversation.click();
+buttons.reply.click();
+buttons.actions.click();
+const selected=Object.fromEntries(Object.entries(buttons).map(([name,button])=>[name,button.attributes['aria-current']||null]));
+navigation.stop();
+process.stdout.write(JSON.stringify({
+  unavailableScrolls,
+  replyDisabled:buttons.reply.attributes['aria-disabled']||null,
+  conversation:targets.conversation.scrolls,
+  reply:targets.reply.scrolls,
+  replyFocuses:targets.reply.focuses,
+  actions:targets.actions.scrolls,
+  selected,
+  listeners:Object.values(buttons).map(button=>Object.keys(button.listeners).length),
+}));
+""")
+
+    assert result == {
+        "unavailableScrolls": 0,
+        "replyDisabled": None,
+        "conversation": [{"block": "start", "behavior": "auto"}],
+        "reply": [{"block": "start", "behavior": "auto"}],
+        "replyFocuses": 1,
+        "actions": [{"block": "start", "behavior": "auto"}],
+        "selected": {
+            "overview": None,
+            "conversation": None,
+            "reply": None,
+            "actions": "location",
+        },
+        "listeners": [0, 0, 0, 0],
+    }
+
+
+def test_mobile_search_preview_navigation_tracks_panel_sections_and_resets_for_next_result():
+    result = run_navigation("""
+const names=['overview','conversation','reply','actions'];
+const buttons=Object.fromEntries(names.map(name=>[name,new FakeElement(name)]));
+const targets=Object.fromEntries(names.map(name=>[name,new FakeElement(name)]));
+const root=new FakeElement('panel');
+let callback; let observedRoot; let disconnected=0;
+const navigation=createNavigation({
+  buttons,targets,root,
+  observe(handler,observed,rootOption){callback=handler; observedRoot=rootOption; return {disconnect(){disconnected++;}};},
+});
+navigation.start();
+callback([{target:targets.overview,isIntersecting:true,intersectionRatio:.2},{target:targets.conversation,isIntersecting:true,intersectionRatio:.8}]);
+navigation.reset(false);
+const selected=Object.fromEntries(Object.entries(buttons).map(([name,button])=>[name,button.attributes['aria-current']||null]));
+navigation.stop();
+process.stdout.write(JSON.stringify({selected,replyDisabled:buttons.reply.attributes['aria-disabled'],observedRoot:observedRoot.name,disconnected}));
+""")
+
+    assert result == {
+        "selected": {"overview": "location", "conversation": None, "reply": None, "actions": None},
+        "replyDisabled": "true",
+        "observedRoot": "panel",
+        "disconnected": 1,
+    }
+
+
+def test_search_preview_ships_mobile_navigation_in_the_offline_bundle():
+    html = (FRONTEND / "index.html").read_text()
+    css = (FRONTEND / "dashboard.css").read_text()
+    navigation_js = CONTROLLER.read_text()
+    bundle = (FRONTEND.parent / "src" / "frontend_bundle.py").read_text()
+    service_worker = (FRONTEND / "service-worker.js").read_text()
+
+    assert '<nav class="mobile-search-preview-nav"' in html
+    assert 'aria-label="Search preview sections"' in html
+    for name, label in (
+        ("overview", "Overview"),
+        ("conversation", "Conversation"),
+        ("reply", "Reply"),
+        ("actions", "Act"),
+    ):
+        assert f'data-search-preview-section="{name}"' in html
+        assert f">{label}</button>" in html
+    assert 'id="search-preview-overview"' in html
+    assert 'id="search-preview-reply-workspace"' in html
+    assert 'id="search-preview-actions"' in html
+    assert '<script src="static/mobile-search-preview-nav.js"></script>' in html
+    assert '"static/mobile-search-preview-nav.js"' in bundle
+    assert "attachMobileSearchPreviewNavigation({document, window})" in navigation_js
+    assert "navigation.reset(!reply.hidden)" in navigation_js
+    assert "attributeFilter:['hidden']" in navigation_js
+    assert "static/mobile-search-preview-nav.js" in service_worker
+    assert ".mobile-search-preview-nav" in css
+    assert "grid-template-columns:repeat(4,minmax(0,1fr))" in css
+    assert "min-height:44px" in css
+    assert "env(safe-area-inset-top)" in css
+    assert "#search-preview-actions { position:static" in css
diff --git a/tests/test_service_worker.py b/tests/test_service_worker.py
index a27534d..8b17d36 100644
--- a/tests/test_service_worker.py
+++ b/tests/test_service_worker.py
@@ -1001,6 +1001,7 @@ def test_install_precaches_complete_subpath_scoped_app_shell():
         "/dashboard/static/mobile-issue-detail-nav.js",
         "/dashboard/static/mobile-update-detail-nav.js",
         "/dashboard/static/mobile-review-detail-nav.js",
+        "/dashboard/static/mobile-search-preview-nav.js",
         "/dashboard/static/checklist-conflict.js",
         "/dashboard/static/voice-transcript-store.js",
         "/dashboard/static/voice-issue-capture.js",