diff --git a/BTCPayServer/wwwroot/css/site.css b/BTCPayServer/wwwroot/css/site.css
index d8d07a167..d459951e3 100644
--- a/BTCPayServer/wwwroot/css/site.css
+++ b/BTCPayServer/wwwroot/css/site.css
@@ -43,3 +43,71 @@ footer {
     width: 100%;
     overflow: hidden;
 }
+
+/* preserving bootstrap3 btn-default now that we migrated to bootstrap4 */
+
+
+.btn-default {
+    color: #333;
+    background-color: #fff;
+    border-color: #ccc;
+}
+
+    .btn-default:focus,
+    .btn-default.focus {
+        color: #333;
+        background-color: #e6e6e6;
+        border-color: #8c8c8c;
+    }
+
+    .btn-default:hover {
+        color: #333;
+        background-color: #e6e6e6;
+        border-color: #adadad;
+    }
+
+    .btn-default:active,
+    .btn-default.active,
+    .open > .dropdown-toggle.btn-default {
+        color: #333;
+        background-color: #e6e6e6;
+        border-color: #adadad;
+    }
+
+        .btn-default:active:hover,
+        .btn-default.active:hover,
+        .open > .dropdown-toggle.btn-default:hover,
+        .btn-default:active:focus,
+        .btn-default.active:focus,
+        .open > .dropdown-toggle.btn-default:focus,
+        .btn-default:active.focus,
+        .btn-default.active.focus,
+        .open > .dropdown-toggle.btn-default.focus {
+            color: #333;
+            background-color: #d4d4d4;
+            border-color: #8c8c8c;
+        }
+
+    .btn-default:active,
+    .btn-default.active,
+    .open > .dropdown-toggle.btn-default {
+        background-image: none;
+    }
+
+    .btn-default.disabled:hover,
+    .btn-default[disabled]:hover,
+    fieldset[disabled] .btn-default:hover,
+    .btn-default.disabled:focus,
+    .btn-default[disabled]:focus,
+    fieldset[disabled] .btn-default:focus,
+    .btn-default.disabled.focus,
+    .btn-default[disabled].focus,
+    fieldset[disabled] .btn-default.focus {
+        background-color: #fff;
+        border-color: #ccc;
+    }
+
+    .btn-default .badge {
+        color: #fff;
+        background-color: #333;
+    }