diff --git a/index.css b/index.css
index ea14690..8349f11 100644
--- a/index.css
+++ b/index.css
@@ -48,6 +48,25 @@ details summary {
     margin-bottom: 1em;
     cursor: pointer;
 }
+details summary::before{
+    content: "[...]";
+    float: right;
+    font-family: monospace;
+    font-style: normal;
+    line-height: 2em;
+    color: white;
+}
+div.flex#intro details summary::before{
+    line-height: 1.2em;
+}
+details[open] summary::before{
+    content: "";
+    float: unset;
+    font-family: unset;
+    font-style: unset;
+    line-height: unset;
+    color: unset;
+}
 
 details {
     color: white;