diff --git a/sppa/calc/index.html b/sppa/calc/index.html
index c2067cb1..83975a40 100644
--- a/sppa/calc/index.html
+++ b/sppa/calc/index.html
@@ -22,6 +22,10 @@
       width: 80%; 
       border-collapse: collapse;
       margin:0;
+      border-spacing: 0;
+    }
+    th, td {
+      margin: 0;
     }
 button {
   font-size:30px;