diff --git a/docs/user_guide.md b/docs/user_guide.md
index e354502..e40a851 100644
--- a/docs/user_guide.md
+++ b/docs/user_guide.md
@@ -229,6 +229,11 @@ the dialog. Opening settings again starts at the menu.
 Phone settings use a screen-width view while open. Closing the dialog restores
 the dashboard's existing scaling. Desktop settings keep their side menus and
 expand/collapse sections.
+Settings switch to the compact layout when the window is at most 700 CSS pixels
+wide. Before phone scaling is enabled, a valid screen width of at most 700 CSS
+pixels also selects it when the browser reports a coarse (touch-style) pointer.
+A small or unavailable screen-width report alone does not select phone settings
+in a wide desktop window, including the Raspberry Pi pywebview desktop.
 
 ### General Settings Pane
 
diff --git a/sensorius/__init__.py b/sensorius/__init__.py
index 3627405..a15fd26 100644
--- a/sensorius/__init__.py
+++ b/sensorius/__init__.py
@@ -4,4 +4,4 @@
 release notes, and supporting tooling can report a consistent build identity.
 """
 
-__version__ = "v0.26.258.2"
+__version__ = "v0.26.259.1"
diff --git a/tests/desktop-settings.spec.js b/tests/desktop-settings.spec.js
new file mode 100644
index 0000000..915dd22
--- /dev/null
+++ b/tests/desktop-settings.spec.js
@@ -0,0 +1,47 @@
+import { test, expect } from '@playwright/test';
+
+// Screen geometry can disagree with the available desktop window geometry.
+for (const screenWidth of [1, 600]) {
+  test(`wide desktop settings ignore a ${screenWidth}px screen report`, async ({ browser, baseURL }) => {
+    const page = await browser.newPage({
+      baseURL,
+      viewport: { width: 1280, height: 900 },
+      screen: { width: screenWidth, height: 900 },
+      hasTouch: false,
+      isMobile: false,
+    });
+    try {
+      await page.route('https://cdn.jsdelivr.net/**', route => route.fulfill({ contentType: 'application/javascript', body: '' }));
+      await page.goto('/', { waitUntil: 'domcontentloaded' });
+      // Confirm the browser really matches the old, faulty screen-only fallback.
+      expect(await page.evaluate(() => matchMedia('(max-device-width:700px)').matches)).toBe(true);
+      await page.getByRole('link', { name: 'Open General Settings' }).click();
+      const general = page.locator('#setupPiModal');
+      await expect(general).toBeVisible();
+      await expect(general).not.toHaveClass(/(^|\s)mobile-settings(\s|$)/);
+      await expect(general.locator('.mobile-settings-nav')).toBeHidden();
+      await expect(general.locator('.system-settings-menu')).toBeVisible();
+      await expect(general.locator('.system-settings-content')).toBeVisible();
+      const display = general.locator('[data-runtime-section="system-display"]');
+      await display.locator(':scope > summary').click();
+      await expect(display.locator('#metric_set')).toBeVisible();
+      await general.getByRole('button', { name: 'Close General Settings' }).click();
+      for (const kind of ['Sensor', 'Switch']) {
+        await page.evaluate(kind => kind === 'Sensor'
+          ? window.editSensorSettings('aht-pr-check')
+          : window.editSwitchSettings('switch-pr-check'), kind);
+        const root = page.locator(`#${kind.toLowerCase()}SettingsModal`);
+        await expect(root).toBeVisible();
+        await expect(root).not.toHaveClass(/(^|\s)mobile-settings(\s|$)/);
+        await expect(root.locator('.mobile-settings-nav')).toBeHidden();
+        await expect(root.locator('.mobile-settings-menu')).toBeVisible();
+        await expect(root.locator('.mobile-settings-content')).toBeVisible();
+        await expect(root.locator('#location')).toBeVisible();
+        await page.goto('/', { waitUntil: 'domcontentloaded' });
+      }
+      await expect(page.locator('meta[name="viewport"]')).toHaveCount(0);
+    } finally {
+      await page.close();
+    }
+  });
+}
diff --git a/ui_static/css/mobile_settings.css b/ui_static/css/mobile_settings.css
index b86b0b8..f764743 100644
--- a/ui_static/css/mobile_settings.css
+++ b/ui_static/css/mobile_settings.css
@@ -1,7 +1,8 @@
 /* Drill-down settings apply only to phone-sized viewports. */
 .mobile-settings-nav, .mobile-settings-chevron { display:none; }
 .mobile-settings-chevron::after { content:'›'; }
-@media (max-width:700px), (max-device-width:700px) {
+/* Keep the screen fallback aligned with phoneQuery in mobile_settings.js. */
+@media (max-width:700px), (min-device-width:1px) and (max-device-width:700px) and (pointer:coarse) {
   .modal-backdrop:has(.mobile-settings), #setupPiModal.mobile-settings {
     padding:.35rem;
     box-sizing:border-box;
diff --git a/ui_static/js/mobile_settings.js b/ui_static/js/mobile_settings.js
index 81008db..857680e 100644
--- a/ui_static/js/mobile_settings.js
+++ b/ui_static/js/mobile_settings.js
@@ -3,7 +3,10 @@
 
 (() => {
 if (window.initMobileSettings) return;
-const phoneQuery = "(max-width: 700px), (max-device-width: 700px)";
+// Phones need the screen fallback before their settings viewport is installed.
+// A missing/small screen report alone must not classify desktop WebKit as mobile.
+// Keep this query aligned with mobile_settings.css.
+const phoneQuery = "(max-width: 700px), (min-device-width: 1px) and (max-device-width: 700px) and (pointer: coarse)";
 const viewportOwners = new Set();
 let settingsViewport = null;
 window.setMobileWorkspaceViewport = function setMobileWorkspaceViewport(root, open, query = phoneQuery) {