tweak core rounded and shadowed to reflect new values

resources/frontend_client/app/css/core/rounded.css

 :root {
-  --default-border-radius: 4px;
+  --default-border-radius: 3px;
 }
 .rounded {
   border-radius: var(--default-border-radius);

resources/frontend_client/app/css/core/shadow.css

 :root {
-    --shadow-color: rgba(0, 0, 0, .07);
+    --shadow-color: rgba(0, 0, 0, .08);
 }
 .shadowed {
-  box-shadow: 0 1px 1px var(--shadow-color);
+  box-shadow: 0 2px 2px var(--shadow-color);
 }