diff --git a/docs/CURRENT-STATE.md b/docs/CURRENT-STATE.md
index 38be0445a..1e9cc00ad 100644
--- a/docs/CURRENT-STATE.md
+++ b/docs/CURRENT-STATE.md
@@ -2796,8 +2796,12 @@ the settings follow. SINCE is a stepped range input (any date, 10, 5, 3, 2 and
 1 years, 6, 3 and 1 months) whose readout names the cut-off date. The panel is
 portable (`street-level-panel` spec in `PanelPositionControls`, minimum
 320 × 280, `dockOnCollapse`): in a resized window the viewer takes the spare
-height and only `.sl-settings` scrolls, and collapsing the window or SHRINK
-after EXPAND docks it at its default size.
+height and only `.sl-settings` scrolls, and a user's collapse, a header
+double-click or SHRINK after EXPAND docks it at its default size (cockpit
+entry, restores and the Cyber accordion never dock a floating window). At
+phone width (≤720 px) the rail is the band between mid-screen and the credit
+line, so the viewer's height is derived from that band instead of 16:10 and
+the whole photo and caption fit without scrolling.
 
 Street-level providers implement the contract documented in
 `src/layers/streetLevel/registry.js`: a definition (`id`, `name`, `label`,
diff --git a/scripts/qa-street-level.mjs b/scripts/qa-street-level.mjs
index a06a9aa18..f18aaeb4e 100644
--- a/scripts/qa-street-level.mjs
+++ b/scripts/qa-street-level.mjs
@@ -621,6 +621,63 @@ async function main() {
         });
       },
     );
+    await step(
+      'on a phone the whole photo fits in the docked panel',
+      async () => {
+        await page.setViewport({
+          width: 390,
+          height: 844,
+          isMobile: true,
+          hasTouch: true,
+        });
+        await sleep(800);
+        if (
+          await page.$eval('#street-level-panel', (node) =>
+            node.classList.contains('collapsed'),
+          )
+        )
+          await page.click(
+            '.panel-collapse-btn[data-collapse-target="street-level-panel"]',
+          );
+        await page.evaluate((id) => {
+          void window.__godsEyeView.dataManager.layers
+            .get('street-level')
+            .module.openImage('mapillary', id);
+        }, firstImageId);
+        await page.waitForFunction(
+          () => {
+            const s = window.__godsEyeView.dataManager.layers
+              .get('street-level')
+              .module.getUIState().street;
+            return (s.imageId && !s.loading) || s.error;
+          },
+          { timeout: 90_000 },
+        );
+        await sleep(600);
+        const fit = await page.evaluate(() => {
+          const inner = document
+            .querySelector('.street-level-panel-inner')
+            .getBoundingClientRect();
+          const meta = document
+            .getElementById('sl-image-meta')
+            .getBoundingClientRect();
+          const viewer = document
+            .getElementById('sl-viewer')
+            .getBoundingClientRect();
+          return {
+            cut: Math.round(meta.bottom - inner.bottom),
+            top: Math.round(viewer.top - inner.top),
+            height: Math.round(viewer.height),
+            overflowX: document.documentElement.scrollWidth > innerWidth,
+          };
+        });
+        assert.ok(fit.cut <= 1, `photo and caption fit (${fit.cut}px cut)`);
+        assert.ok(fit.height >= 100, `viewer stays usable (${fit.height}px)`);
+        assert.equal(fit.overflowX, false, 'no sideways scroll');
+        await page.setViewport(VIEWPORTS[0]);
+        await sleep(600);
+      },
+    );
     await step('no page errors', () => {
       assert.deepEqual(errors, []);
     });
diff --git a/src/streetLevelMarkup.test.mjs b/src/streetLevelMarkup.test.mjs
index 320c0d55b..9e327bec7 100644
--- a/src/streetLevelMarkup.test.mjs
+++ b/src/streetLevelMarkup.test.mjs
@@ -122,6 +122,19 @@ test('labels say what the buttons do', () => {
   );
 });
 
+test('on phones the viewer is sized from the rail band, not its aspect ratio', () => {
+  assert.match(
+    panelCss,
+    /@media \(max-width: 720px\) \{\s*\.sl-viewer \{[^}]*height: clamp\(/,
+  );
+  // Floating and expanded viewers must not inherit the phone height.
+  for (const selector of [
+    ".panel-floating\\[style\\*='height'\\] \\.sl-viewer",
+    '\\.sl-viewer-wrap-expanded \\.sl-viewer',
+  ])
+    assert.match(panelCss, new RegExp(`${selector} \\{[^}]*height: auto`));
+});
+
 test('the viewer comes first and the panel is a portable, resizable window', () => {
   const controlsBlock = html.slice(html.indexOf('<fieldset id="sl-controls"'));
   assert.ok(
diff --git a/src/ui/styles/street-level.css b/src/ui/styles/street-level.css
index 5888bd3c5..af7458734 100644
--- a/src/ui/styles/street-level.css
+++ b/src/ui/styles/street-level.css
@@ -461,6 +461,7 @@ button.sl-status:focus-visible {
 
 .panel-floating[style*='height'] .sl-viewer {
   flex: 1 1 auto;
+  height: auto;
   min-height: 0;
   aspect-ratio: auto;
 }
@@ -497,6 +498,7 @@ button.sl-status:focus-visible {
 
 .sl-viewer-wrap-expanded .sl-viewer {
   flex: 1 1 auto;
+  height: auto;
   min-height: 0;
   aspect-ratio: auto;
 }
@@ -541,3 +543,16 @@ button.sl-status:focus-visible {
     min-height: 150px;
   }
 }
+
+/* ── Phones ──────────────────────────────────────────────────────────────── */
+/* At this width the right rail is the band between mid-screen and the credit
+   line (responsive.css: top 50vh + 8px, bottom 2vh + 7.5rem). Size the photo
+   from that band, less the panel's header, tool bar and caption (~150px), so
+   the whole image shows without scrolling; EXPAND still gives full screen. */
+@media (max-width: 720px) {
+  .sl-viewer {
+    aspect-ratio: auto;
+    height: clamp(110px, calc(48vh - 8px - 7.5rem - 150px), 320px);
+    min-height: 0;
+  }
+}