make buttons responsive when more added

style.css

@@ -50,6 +50,7 @@ div.buttons {
     display: flex;
     justify-content: center;
     align-items: center;
+    max-width: 480px;
     margin: 0 auto;
     position: absolute;
     bottom: 50px;
@@ -63,10 +64,12 @@ ul.buttons {
     padding: 0;
     padding-left: 10px;
     display: flex;
+    flex-wrap: wrap;
 }
 
 ul.buttons li {
     margin-right: 3px;
+    line-height: 1;
 }
 
 div.footer {