diff --git a/e2e/tests/journeys.spec.ts b/e2e/tests/journeys.spec.ts
index 65d3812..e4060de 100644
--- a/e2e/tests/journeys.spec.ts
+++ b/e2e/tests/journeys.spec.ts
@@ -2826,6 +2826,52 @@ test('nearby schools link on to other schools and into compare', async ({ page }
   expect(Math.abs(offsetAfter - offsetBefore)).toBeLessThanOrEqual(8);
 });
 
+/**
+ * Every section in the mobile jump sheet can actually be reached.
+ *
+ * The sheet is a fixed bottom sheet, and the app has a fixed bottom tab bar.
+ * `position: sticky` with a z-index on the sticky nav makes it a stacking
+ * context, so the sheet's own z-index orders it only within that context —
+ * against the tab bar, the nav's value is what counts. The last item in the
+ * sheet was therefore painted over and untappable as soon as the list grew
+ * long enough to reach the bar, which adding "Nearby schools" is what did.
+ *
+ * Bounding boxes are not enough to catch this: the item is in the viewport and
+ * the right size, it is simply underneath something. So this asks the question
+ * a thumb asks — what is on top at this point.
+ */
+test('every section in the mobile jump sheet is tappable, not under the tab bar', async ({ page }) => {
+  await page.setViewportSize({ width: 390, height: 844 });
+  await searchByName(page, 'Primary');
+  await schoolLinks(page).first().click();
+  await page.waitForURL(/\/school\//);
+
+  // Scroll down so the sticky nav is docked and the sheet has somewhere to open.
+  await page.evaluate(() => window.scrollTo({ top: 1200 }));
+  // Two controls carry aria-haspopup: the mobile "Section" button and the
+  // desktop "All" one, which is display:none here but still in the DOM.
+  await page.locator('[aria-haspopup="menu"]:visible').click();
+
+  const sheet = page.locator('[role="menu"]');
+  await expect(sheet).toBeVisible();
+
+  const covered = await sheet.evaluate((panel: HTMLElement) =>
+    Array.from(panel.querySelectorAll('[role="menuitem"]'))
+      .map((el) => {
+        const box = el.getBoundingClientRect();
+        const hit = document.elementFromPoint(
+          Math.round(box.left + box.width / 2),
+          Math.round(box.top + box.height / 2),
+        );
+        return { label: (el as HTMLElement).innerText.trim().replace(/\s+/g, ' '), reachable: !!(hit && hit.closest('[role="menuitem"]')) };
+      })
+      .filter((item) => !item.reachable)
+      .map((item) => item.label),
+  );
+
+  expect(covered).toEqual([]);
+});
+
 /**
  * The nearby-schools section at MOBILE.md's three reference widths.
  *
diff --git a/nextjs-app/components/school/SchoolDetailShell.module.css b/nextjs-app/components/school/SchoolDetailShell.module.css
index 1e0ee6f..c519195 100644
--- a/nextjs-app/components/school/SchoolDetailShell.module.css
+++ b/nextjs-app/components/school/SchoolDetailShell.module.css
@@ -283,6 +283,21 @@
 }
 
 
+/* `position: sticky` with a z-index makes .sectionNav a stacking context, so
+   the jump sheet's own z-index only orders it INSIDE that context. Against the
+   fixed bottom tab bar (Navigation.module.css, z-index 1000) what counts is
+   .sectionNav's 10 — which is why the sheet's last item was painted over, and
+   untappable, once the list grew long enough to reach the bar.
+
+   Lifted only while the sheet is open, and only to 1100: above the bar, below
+   the comparison toast (2000), the fullscreen map (5000) and the info popover
+   (9999). This rule carries the z-index and nothing else; every other
+   declaration belongs to .sectionNav in both states. */
+.sectionNavSheetOpen {
+    z-index: 1100;
+}
+
+
 .sectionNavBack {
     flex: none;
     display: inline-flex;
diff --git a/nextjs-app/components/school/SchoolDetailShell.tsx b/nextjs-app/components/school/SchoolDetailShell.tsx
index 04e7e52..ad81630 100644
--- a/nextjs-app/components/school/SchoolDetailShell.tsx
+++ b/nextjs-app/components/school/SchoolDetailShell.tsx
@@ -344,7 +344,10 @@ export function SchoolDetailShell({
       </header>
 
       {/* Sticky Section Navigation — docks under the global header */}
-      <nav className={styles.sectionNav} aria-label="Page sections">
+      <nav
+        className={`${styles.sectionNav}${sectionsOpen ? ` ${styles.sectionNavSheetOpen}` : ''}`}
+        aria-label="Page sections"
+      >
         <button onClick={scrollToTop} className={styles.sectionNavBack} aria-label="Back to top">
           <span aria-hidden="true">↑</span>
           <span className={styles.sectionNavBackLabel}>Top</span>