collapse comment by clicking on indent line

static/style.css

@@ -1368,6 +1368,7 @@ a.search_subreddit:hover {
     margin: 10px 0;
     border-radius: 5px;
     display: flex;
+    position: relative;
 }
 
 .comment img {
@@ -1459,6 +1460,18 @@ a.search_subreddit:hover {
     flex: 0 1 auto;
 }
 
+.comment_indent {
+    position: absolute;  /* relative to .comment */
+    left: 15px;
+    width: 20px;
+    top: 45px;
+    height: calc(100% - 45px);
+}
+
+.comment:has(> .comment_right > .comment_data > .comment_indent:hover) > .comment_left * {
+    background: var(--highlighted);
+}
+
 .comment_image {
     max-width: 500px;
     align-self: center;

templates/comment.html

@@ -34,6 +34,7 @@
 			</span>
 			{% endfor %}
 			{% endif %}
+			<div class="comment_indent"></div>
 		</summary>
 		{% if is_filtered %}
 		<div class="comment_body_filtered {% if highlighted %}highlighted{% endif %}">(Filtered content)</div>