diff --git a/lib/asciinema_web/controllers/recording/thumbnail.html.heex b/lib/asciinema_web/controllers/recording/thumbnail.html.heex
index 800757e28..1ecbf162b 100644
--- a/lib/asciinema_web/controllers/recording/thumbnail.html.heex
+++ b/lib/asciinema_web/controllers/recording/thumbnail.html.heex
@@ -1,3 +1,3 @@
-<div class="thumbnail">
+<div class="thumbnail" style={"border-right: 1ch solid #{theme(@asciicast).bg}"}>
   <RecordingSVG.thumbnail asciicast={@asciicast} />
 </div>
diff --git a/lib/asciinema_web/controllers/recording_html.ex b/lib/asciinema_web/controllers/recording_html.ex
index 27c5de206..b25f84ae1 100644
--- a/lib/asciinema_web/controllers/recording_html.ex
+++ b/lib/asciinema_web/controllers/recording_html.ex
@@ -10,6 +10,7 @@ defmodule AsciinemaWeb.RecordingHTML do
   defdelegate author_username(asciicast), to: MediaView
   defdelegate author_avatar_url(asciicast), to: MediaView
   defdelegate author_profile_path(asciicast), to: MediaView
+  defdelegate theme(asciicast), to: Media
   defdelegate theme_name(asciicast), to: Media
   defdelegate theme_options, to: MediaView
   defdelegate font_family_options, to: MediaView