Button demo cosmetics

src/views/button/ButtonDemo.vue

@@ -77,12 +77,18 @@ export default {
 </script>
 
 <style lang="scss" scoped>
-button {
-    margin-right: .5em;
+.p-button {
+    margin-right: .5rem;
+}
+
+.p-buttonset {
+    .p-button {
+        margin-right: 0;
+    }
 }
 
 .sizes {
-    .p-button {
+    .button {
         margin-bottom: .5rem;
         display: block;
 
@@ -91,4 +97,21 @@ button {
         }
     }
 }
+
+@media screen and (max-width: 960px) {
+    .p-button {
+        margin-bottom: .5rem;
+
+        &:not(.p-button-icon-only) {
+            display: flex;
+            width: 100%;
+        }
+    }
+
+    .p-buttonset {
+        .p-button {
+            margin-bottom: 0;
+        }
+    }
+}
 </style>