Use a class

app/assets/stylesheets/events.css

@@ -46,6 +46,11 @@
   z-index: 1;
 }
 
+.event__timestamp {
+  display: grid;
+  align-self: start;
+}
+
 .event__wrapper {
   align-content: end;
   display: grid;
@@ -58,9 +63,4 @@
     grid-column-start: unset !important;
     grid-row-start: unset !important;
   }
-
-  time {
-    display: grid;
-    align-self: start;
-  }
 }

app/views/events/_day.html.erb

@@ -12,7 +12,7 @@
         <%= event_cluster_tag(*hour_column) do %>
           <%= render cluster %>
 
-          <time class="txt-small translucent" data-local-time-target="time" datetime="<%= cluster.first.created_at.strftime("%H:%M") %>">
+          <time class="event__timestamp txt-small translucent" data-local-time-target="time" datetime="<%= cluster.first.created_at.strftime("%H:%M") %>">
             <%= cluster.first.created_at.strftime("%l:%M %P").strip %>
           </time>
         <% end %>