use centered h2 for 2FA page headers

core/css/styles.css

@@ -32,6 +32,10 @@ body {
 	background-size: cover;
 }
 
+.two-factor-header {
+	text-align: center;
+}
+
 .two-factor-provider {
 	text-align: center;
 	width: 100%;

core/templates/twofactorselectchallenge.php

@@ -1,22 +1,22 @@
-<fieldset class="warning">
-		<legend><strong><?php p($l->t('Two-step verification')) ?></strong></legend>
-		<p><?php p($l->t('Enhanced security has been enabled for your account. Please authenticate using a second factor.')) ?></p>
-</fieldset>
-<fieldset class="warning">
-<ul>
-<?php foreach ($_['providers'] as $provider): ?>
-	<li>
-		<a class="two-factor-provider"
-		   href="<?php p(\OC::$server->getURLGenerator()->linkToRoute('core.TwoFactorChallenge.showChallenge',
-							[
-								'challengeProviderId' => $provider->getId(),
-								'redirect_url' => $_['redirect_url'],
-							]
-						)) ?>">
-			<?php p($provider->getDescription()) ?>
-		</a>
-	</li>
-<?php endforeach; ?>
-</ul>
-</fieldset>
+<div class="warning">
+	<h2 class="two-factor-header"><?php p($l->t('Two-step verification')) ?></h2>
+	<p><?php p($l->t('Enhanced security has been enabled for your account. Please authenticate using a second factor.')) ?></p>
+	<p>
+		<ul>
+			<?php foreach ($_['providers'] as $provider): ?>
+				<li>
+					<a class="two-factor-provider"
+					   href="<?php p(\OC::$server->getURLGenerator()->linkToRoute('core.TwoFactorChallenge.showChallenge',
+										[
+											'challengeProviderId' => $provider->getId(),
+											'redirect_url' => $_['redirect_url'],
+										]
+									)) ?>">
+						<?php p($provider->getDescription()) ?>
+					</a>
+				</li>
+			<?php endforeach; ?>
+		</ul>
+	</p>
+</div>
 <a class="two-factor-cancel" <?php print_unescaped($_['logout_attribute']); ?>><?php p($l->t('Cancel log in')) ?></a>

core/templates/twofactorshowchallenge.php

@@ -10,7 +10,7 @@ $template = $_['template'];
 ?>
 
 <div class="warning">
-		<h2><?php p($provider->getDisplayName()); ?></h2>
+		<h2 class="two-factor-header"><?php p($provider->getDisplayName()); ?></h2>
 		<?php if ($error): ?>
 		<p><?php p($l->t('An error occured while verifying the token')); ?></p>
 		<?php endif; ?>