diff --git a/client/src/templates/Challenges/components/completion-modal.css b/client/src/templates/Challenges/components/completion-modal.css
index a532e368ae..bd4ee5bda3 100644
--- a/client/src/templates/Challenges/components/completion-modal.css
+++ b/client/src/templates/Challenges/components/completion-modal.css
@@ -35,6 +35,11 @@
   animation: success-icon-animation 150ms linear 100ms forwards;
 }
 
+.challenge-success-modal .btn-cta-big {
+  max-width: 100%;
+  font-size: 1.3rem;
+}
+
 @keyframes success-icon-animation {
   100% {
     opacity: 1;
@@ -95,9 +100,12 @@
 
 @media screen and (max-width: 991px) {
   .challenge-success-modal .btn-lg {
-    font-size: 16px;
+    font-size: 1rem;
+  }
+  .challenge-success-modal .btn-cta-big {
+    max-width: 100%;
+    font-size: 1rem;
   }
-
   .completion-modal-body {
     min-height: 340px;
   }