diff --git a/layouts/_default/bookmarks.html b/layouts/_default/bookmarks.html
index bc0d82c..f1c45a4 100644
--- a/layouts/_default/bookmarks.html
+++ b/layouts/_default/bookmarks.html
@@ -2,7 +2,9 @@
 <main class="h-feed hfeed" itemscope itemtype="https://schema.org/DataFeed">
 	<h1 id="bookmarks" class="p-name" itemprop="name headline">My book&shy;marks</h1>
 	{{ .Content }}
-	<p><em>Timestamp format: <code>YYYY-MM-DD HH:MM</code>, as per <cite><a href="https://www.ietf.org/rfc/rfc3339.txt">RFC 3339</a></cite></em></p>
+	<p role="doc-tip">
+		Timestamp format: <code>YYYY-MM-DD HH:MM</code>, as per <cite><a href="https://www.ietf.org/rfc/rfc3339.txt">RFC 3339</a></cite>
+	</p>
 	<ul class="unstyled-list">
 		{{ $bookmarks := getJSON "https://seirdy.one/data/bookmarks.json" -}}
 		{{ range sort $bookmarks "tags" "desc" -}}
diff --git a/layouts/partials/posts.html b/layouts/partials/posts.html
index 176226c..c6657a2 100644
--- a/layouts/partials/posts.html
+++ b/layouts/partials/posts.html
@@ -10,7 +10,9 @@
 	<p>Here's a selection of my best posts. To see the rest, visit <a href="/posts.html">my Posts page</a>.</p>
 {{- end }}
 	<p>I edit some of these posts quite often; some are updated indefinitely. Check the "updated" timestamps.</p>
-	<p><em>Timestamp format: <code>YYYY-MM-DD</code>, as per <cite><a href="https://www.ietf.org/rfc/rfc3339.txt">RFC 3339</a></cite> and <cite><a href="https://xkcd.com/1179/">ISO 8601</a></cite></em></p>
+	<p role="doc-tip">
+		Timestamp format: <code>YYYY-MM-DD</code>, as per <cite><a href="https://www.ietf.org/rfc/rfc3339.txt">RFC 3339</a></cite> and <cite><a href="https://xkcd.com/1179/">ISO 8601</a></cite>
+	</p>
 	<ol class="unstyled-list" reversed>
 		{{- range where site.RegularPages "Type" "in" site.Params.mainSections -}}
 		{{- if or ($isStandalone) (.Params.featured) }}