diff --git a/static/js/cours.js b/static/js/cours.js
index 30ece9a..82cff88 100644
--- a/static/js/cours.js
+++ b/static/js/cours.js
@@ -102,6 +102,14 @@ window.addEventListener("load", () => {
       fileTreeElement.querySelector("ul").childNodes
     );
 
+    // Bold opened file
+    const opened_file = fullpath.split("/").at(-1);
+    last_openeded.querySelector("ul").childNodes.forEach((el) => {
+      if (el.innerText === opened_file) {
+        el.style.fontWeight = "bold";
+      }
+    });
+
     uncollapse(last_openeded);
   }
 });