fix: use rem

Author: thomasguillot

patterns/header/header-mobile-style-1.php

@@ -26,7 +26,7 @@
 		<!-- wp:group {"style":{"spacing":{"blockGap":"var:preset|spacing|20"}},"layout":{"type":"flex","flexWrap":"nowrap"}} -->
 		<div class="wp-block-group">
 			<?php if ( class_exists( 'Newspack\Reader_Activation' ) && \Newspack\Reader_Activation::is_enabled() ) : ?>
-				<!-- wp:newspack/my-account-button {"className":"is-style-icon-only has-x-small-size","style":{"spacing":{"padding":{"top":"var:custom|spacing|15","bottom":"var:custom|spacing|15","left":"var:custom|spacing|15","right":"var:custom|spacing|15"}},"elements":{"link":{"color":{"text":"var:preset|color|contrast"}}}},"backgroundColor":"base","textColor":"contrast","fontSize":"x-small"} /-->
+				<!-- wp:newspack/my-account-button {"className":"is-style-icon-only has-x-small-size","style":{"spacing":{"padding":{"top":"0.375rem","bottom":"0.375rem","left":"0.375rem","right":"0.375rem"}},"elements":{"link":{"color":{"text":"var:preset|color|contrast"}}}},"backgroundColor":"base","textColor":"contrast","fontSize":"x-small"} /-->
 			<?php endif; ?>
 
 			<!-- wp:buttons {"layout":{"type":"flex","flexWrap":"nowrap"},"style":{"spacing":{"blockGap":"var:preset|spacing|20"}}} -->

patterns/header/header-mobile-style-2.php

@@ -20,7 +20,7 @@
 		<!-- wp:site-logo {"width":256,"lock":{"move":false,"remove":true}} /-->
 
 		<?php if ( class_exists( 'Newspack\Reader_Activation' ) && \Newspack\Reader_Activation::is_enabled() ) : ?>
-			<!-- wp:newspack/my-account-button {"className":"is-style-icon-only has-x-small-size","style":{"spacing":{"padding":{"top":"var:custom|spacing|15","bottom":"var:custom|spacing|15","left":"var:custom|spacing|15","right":"var:custom|spacing|15"}},"elements":{"link":{"color":{"text":"var:preset|color|contrast"}}}},"backgroundColor":"base","textColor":"contrast","fontSize":"x-small"} /-->
+			<!-- wp:newspack/my-account-button {"className":"is-style-icon-only has-x-small-size","style":{"spacing":{"padding":{"top":"0.375rem","bottom":"0.375rem","left":"0.375rem","right":"0.375rem"}},"elements":{"link":{"color":{"text":"var:preset|color|contrast"}}}},"backgroundColor":"base","textColor":"contrast","fontSize":"x-small"} /-->
 		<?php else : ?>
 			<!-- wp:template-part {"slug":"search-menu","theme":"newspack-block-theme","tagName":"div","className":"search-menu"} /-->
 		<?php endif; ?>

patterns/header/header-mobile-style-3.php

@@ -22,7 +22,7 @@
 			<?php if ( class_exists( 'Newspack\Reader_Activation' ) && \Newspack\Reader_Activation::is_enabled() ) : ?>
 				<!-- wp:template-part {"slug":"search-menu","theme":"newspack-block-theme","tagName":"div","className":"search-menu"} /-->
 
-				<!-- wp:newspack/my-account-button {"className":"is-style-icon-only has-x-small-size","style":{"spacing":{"padding":{"top":"var:custom|spacing|15","bottom":"var:custom|spacing|15","left":"var:custom|spacing|15","right":"var:custom|spacing|15"}},"elements":{"link":{"color":{"text":"var:preset|color|contrast"}}}},"backgroundColor":"base","textColor":"contrast","fontSize":"x-small"} /-->
+				<!-- wp:newspack/my-account-button {"className":"is-style-icon-only has-x-small-size","style":{"spacing":{"padding":{"top":"0.375rem","bottom":"0.375rem","left":"0.375rem","right":"0.375rem"}},"elements":{"link":{"color":{"text":"var:preset|color|contrast"}}}},"backgroundColor":"base","textColor":"contrast","fontSize":"x-small"} /-->
 			<?php else : ?>
 				<!-- wp:buttons {"layout":{"type":"flex","flexWrap":"nowrap"},"style":{"spacing":{"blockGap":"var:preset|spacing|20"}}} -->
 				<div class="wp-block-buttons">