diff --git a/resources/views/mails/preview.blade.php b/resources/views/mails/preview.blade.php
index b966354..3d43892 100644
--- a/resources/views/mails/preview.blade.php
+++ b/resources/views/mails/preview.blade.php
@@ -1,9 +1,9 @@
-<div class="w-full h-screen">
+<div style="width: 100%; height: 75vh;">
     <iframe
         srcdoc="{{ $html }}"
         sandbox
         referrerpolicy="no-referrer"
         title="{{ __('Email preview') }}"
-        class="w-full h-full max-w-full" style="width: 100vw; height: 100vh; border: none;">
+        style="display: block; width: 100%; height: 100%; border: none;">
     </iframe>
 </div>
diff --git a/tests/MailRouteSecurityTest.php b/tests/MailRouteSecurityTest.php
index 649baed..f777f1c 100644
--- a/tests/MailRouteSecurityTest.php
+++ b/tests/MailRouteSecurityTest.php
@@ -162,3 +162,13 @@ function downloadUrl(Mail $mail, $attachment): string
         ->toContain('referrerpolicy="no-referrer"')
         ->not->toContain('src="');
 });
+
+it('sizes the inline preview to its container rather than the viewport', function () {
+    $preview = view('mails::mails.preview', ['html' => '<p>Preview</p>'])->render();
+
+    // A viewport-wide frame inside a narrower card puts a centred email past
+    // the card's right edge, so the preview looks empty.
+    expect($preview)
+        ->toContain('width: 100%')
+        ->not->toContain('100vw');
+});