add custom stylesheet ¯\_(ツ)_/¯

functions.php

@@ -0,0 +1,8 @@
+<?php
+
+add_action('init', 'custom_stylesheet');
+ 
+function custom_stylesheet() {
+    wp_register_style( 'custom-styles', get_template_directory_uri() . '/style.css' );
+}
+wp_enqueue_style( 'custom-styles' );

style.css

@@ -20,3 +20,31 @@ This theme, like WordPress, is licensed under the GPL.
 Use it to make something cool, have fun, and share what you've learned
 with others.
 */
+
+.wp-site-blocks h2 {
+  display: flex;
+  height: 36px;
+  align-items: center;
+  border-bottom: 1px solid;
+}
+
+
+.wp-site-blocks h2::before {
+  content: "";
+  border-top: 1px solid;
+  border-right: 1px solid;
+  width: 80px;
+  margin-right: 8px;
+  height: 36px;
+  border-bottom: 1px solid #f5fbf8;
+}
+
+.wp-site-blocks h2::after {
+  content: "";
+  border-top: 1px solid;
+  flex-grow: 1;
+  margin-left: 8px;
+  height: 36px;
+  border-left: 1px solid;
+  border-bottom: 1px solid #f5fbf8;
+}