Update examples, add css

examples/assets/custom_assets.css

@@ -0,0 +1,12 @@
+body {
+    background-color: #f0f0f0;
+    font-family: Arial, sans-serif;
+    margin: 0;
+    padding: 0;
+    display: flex;
+    justify-content: center;
+    align-items: center;
+    text-align: center;
+    height: 100vh;
+    width: 100vw;
+}