diff --git a/tests/Browser/FieldsTest.php b/tests/Browser/FieldsTest.php
index 5caee010..23f330fc 100644
--- a/tests/Browser/FieldsTest.php
+++ b/tests/Browser/FieldsTest.php
@@ -148,11 +148,17 @@ it('opens the customizable select picker as M3\'s menu, where the browser suppor
     $select = "document.querySelector('#hours-field')";
     $option = "{$select}.querySelector('option')";
 
-    $page = fieldProbe()
-        // menu.css only styles the picker inside @supports (appearance: base-select), so this
-        // also confirms the browser running the suite actually has it.
-        ->assertScript("CSS.supports('appearance', 'base-select') === true")
-        ->assertScript("getComputedStyle({$select}).appearance === 'base-select'");
+    $page = fieldProbe();
+
+    // menu.css only styles the picker inside @supports (appearance: base-select). A browser without
+    // it (Firefox) keeps its own native picker, which is the fallback, and there is no M3 menu to open.
+    if ($page->script("CSS.supports('appearance', 'base-select')") !== true) {
+        $page->assertScript("getComputedStyle({$select}).appearance !== 'base-select'");
+
+        return;
+    }
+
+    $page->assertScript("getComputedStyle({$select}).appearance === 'base-select'");
 
     $page->click('#hours-field')
         ->assertScript("{$select}.matches(':open')")