Does this possibly work?

app/public/css/custom.css

@@ -16,16 +16,16 @@
 main > .container {
     padding: 60px 15px 0;
 }
-  
+
 .footer {
     background-color: #f5f5f5;
 }
-  
+
 .footer > .container {
     padding-right: 15px;
     padding-left: 15px;
 }
-  
+
 code {
     font-size: 80%;
 }
@@ -42,25 +42,28 @@ code {
       padding-bottom: 6rem;
     }
   }
-  
+
   .jumbotron p:last-child {
     margin-bottom: 0;
   }
-  
+
   .jumbotron h1 {
     font-weight: 300;
   }
-  
+
   .jumbotron .container {
     max-width: 40rem;
   }
-  
+
   footer {
     padding-top: 3rem;
     padding-bottom: 3rem;
   }
-  
+
   footer p {
     margin-bottom: .25rem;
   }
-  
+
+  .card .mx-auto {
+    margin-bottom: 50px;
+  }