diff --git a/examples/server/public/index.html b/examples/server/public/index.html
index f992b60a1..9b261d154 100644
--- a/examples/server/public/index.html
+++ b/examples/server/public/index.html
@@ -198,7 +198,7 @@
             </label>
           </template>
           <!-- TODO: add more sampling-related configs, please regroup them into different "collapse" sections -->
-          <div class="collapse collapse-plus bg-base-200 mb-2">
+          <div class="collapse collapse-arrow bg-base-200 mb-2">
             <input type="checkbox" />
             <div class="collapse-title font-bold">Advanced config</div>
             <div class="collapse-content">