fix(docs): add width/height to icons

Author: bcakmakoglu

docs/examples/math/style.css

@@ -80,6 +80,11 @@
   justify-content: center;
 }
 
+.vue-flow__node-operator button svg {
+  width: 100%;
+  height: 100%;
+}
+
 .vue-flow__node-operator button:hover {
   background-color: #0EA5E9;
   transition: background-color 0.2s;