diff --git a/_layouts/default.html b/_layouts/default.html
index 8477ce3..60ec9b5 100644
--- a/_layouts/default.html
+++ b/_layouts/default.html
@@ -146,7 +146,7 @@ <h3><br />{{ site.description | default: site.github.project_tagline }}</h3>
       </p>
 
       <a target="_blank" href="https://checkout.opennode.com/p/3dbad724-90f5-4616-93bc-a9907d5dd831"
-        class="button button2">TABConf 7 (BTC)</a>
+        class="button button4">TABConf 7 (BTC)</a>
       <a target="_blank" href="https://buy.stripe.com/eVa9Cf3UTfaXcE06ox" class="button button3">TABConf 7 (Fiat)</a>
       <br>