diff --git a/web/css/mrbs.css.php b/web/css/mrbs.css.php
index 0fc6b27b3..214f499d6 100644
--- a/web/css/mrbs.css.php
+++ b/web/css/mrbs.css.php
@@ -657,14 +657,21 @@
   content: '\00203a';  /* Single left-pointing angle quotation mark */
 }
 
-nav a.prev_week::before {
+nav a.prev.week::before {
   content: '\0000ab';  /* Left-pointing double angle quotation mark */
 }
 
-nav a.next_week::before {
+nav a.next.week::before {
   content: '\0000bb';  /* Right-pointing double angle quotation mark */
 }
 
+<?php // Don't display the << and >> buttons on narrow screens ?>
+@media (max-width: 30rem) {
+  nav a.week {
+    display: none;
+  }
+}
+
 .message_top {
   font-weight: bold;
   color: red;
diff --git a/web/index.php b/web/index.php
index bdaf308ac..b12144f85 100644
--- a/web/index.php
+++ b/web/index.php
@@ -313,14 +313,14 @@ function get_arrow_nav(string $view, int $view_all, int $year, int $month, int $
   $html .= "<nav class=\"arrow\">\n";
   if ($view == 'day')
   {
-    $html .= "<a class=\"prev_week symbol prefetch\" title=\"$title_prev_week\" aria-label=\"$title_prev_week\" href=\"" . htmlspecialchars($link_prev_week) . "\"></a>";
+    $html .= "<a class=\"prev week symbol prefetch\" title=\"$title_prev_week\" aria-label=\"$title_prev_week\" href=\"" . htmlspecialchars($link_prev_week) . "\"></a>";
   }
   $html .= "<a class=\"prev symbol prefetch\" title=\"$title_prev\" aria-label=\"$title_prev\" href=\"" . htmlspecialchars($link_prev) . "\"></a>";
   $html .= "<a title= \"$title_this\" aria-label=\"$title_this\" href=\"" . htmlspecialchars($link_today) . "\">" . get_vocab('today') . "</a>";
   $html .= "<a class=\"next symbol prefetch\" title=\"$title_next\" aria-label=\"$title_next\" href=\"" . htmlspecialchars($link_next) . "\"></a>";
   if ($view == 'day')
   {
-    $html .= "<a class=\"next_week symbol prefetch\" title=\"$title_next_week\" aria-label=\"$title_next_week\" href=\"" . htmlspecialchars($link_next_week) . "\"></a>";
+    $html .= "<a class=\"next week symbol prefetch\" title=\"$title_next_week\" aria-label=\"$title_next_week\" href=\"" . htmlspecialchars($link_next_week) . "\"></a>";
   }
   $html .= "</nav>";