diff --git a/resources/views/mail/theme.blade.php b/resources/views/mail/theme.blade.php
index 910d6527..3dff94a4 100644
--- a/resources/views/mail/theme.blade.php
+++ b/resources/views/mail/theme.blade.php
@@ -203,7 +203,7 @@ img {
     width: 100%;
 }
 
-/* Header: the app name in title-lg, or the configured logo */
+/* Header: the app name in title-lg (22/28 at weight 400), or the configured logo */
 
 .header {
     padding: 32px 0 24px;
@@ -213,7 +213,7 @@ img {
 .header a {
     color: {{ $role['on-surface'] }};
     font-size: 22px;
-    font-weight: 500;
+    font-weight: 400;
     letter-spacing: 0;
     line-height: 28px;
     text-decoration: none;
@@ -226,7 +226,7 @@ img {
     margin: 0 auto;
 }
 
-/* Body: the card, separated from the page by tone alone */
+/* Body: the card, separated from the page by tone alone, on M3's extra-large corner */
 
 .body {
     -premailer-cellpadding: 0;
@@ -245,7 +245,7 @@ img {
     -premailer-width: 570px;
     background-color: {{ $card }};
     border: 0;
-    border-radius: 24px;
+    border-radius: 28px;
     margin: 0 auto;
     padding: 0;
     width: 570px;
diff --git a/tests/Feature/MailThemeTest.php b/tests/Feature/MailThemeTest.php
index cc4dca63..ee8a1dfe 100644
--- a/tests/Feature/MailThemeTest.php
+++ b/tests/Feature/MailThemeTest.php
@@ -118,7 +118,7 @@ it('inlines the application\'s scheme onto the mail', function () {
         ->toContain('border-top: 16px solid #123456')
         ->toContain('color: #fefefe')
         ->toContain('border-radius: 9999px')
-        ->and(inlineStyle($html, 'inner-body'))->toContain('background-color: #fdfdfd')
+        ->and(inlineStyle($html, 'inner-body'))->toContain('background-color: #fdfdfd')->toContain('border-radius: 28px')
         ->and(inlineStyle($html, 'wrapper'))->toContain('background-color: #eeeeee')
         ->and(inlineStyle($html, 'panel-content'))->toContain('background-color: #eeeeee')
         ->and($html)
@@ -190,6 +190,19 @@ it('styles every button colour Laravel and M3 name', function () {
     expect($css)->not->toContain('@media');
 });
 
+it('keeps every corner and weight on M3\'s scales', function () {
+    $css = view('livewire-material::mail.theme')->render();
+
+    preg_match_all('/border-radius: (\d+)px/', $css, $corners);
+
+    // M3's shape scale, plus the `full` corner a button draws as a large pixel value.
+    expect(array_unique($corners[1]))->each->toBeIn(['0', '4', '8', '12', '16', '20', '28', '32', '48', '9999'])
+        ->and($css)->toContain(<<<'CSS'
+            .header a {
+            CSS)
+        ->toMatch('/\.header a \{[^}]*font-weight: 400/');
+});
+
 it('leaves the application\'s mail components alone unless asked', function () {
     expect(config('mail.markdown.paths'))->not->toContain(LivewireMaterialServiceProvider::mailComponentPath());