feat(examples): add validation example

src/style.css

@@ -102,13 +102,10 @@
 
 .react-flow__node {
   position: absolute;
-  color: #222;
-  text-align: center;
   user-select: none;
   pointer-events: all;
   transform-origin: 0 0;
   cursor: grab;
-  background: #eee;
 
   &.selected,
   &.selected:hover {
@@ -124,28 +121,28 @@
   }
 }
 
-.react-flow__node-default {
-  padding: 10px;
-  border-radius: 5px;
-  width: 150px;
-  background: #ff6060;
-  font-size: 12px;
-}
-
-.react-flow__node-input {
-  padding: 10px;
-  border-radius: 5px;
-  width: 150px;
-  background: #9999ff;
-  font-size: 12px;
-}
-
+.react-flow__node-default,
+.react-flow__node-input,
 .react-flow__node-output {
   padding: 10px;
   border-radius: 5px;
   width: 150px;
-  background: #55dd99;
   font-size: 12px;
+  color: #222;
+  text-align: center;
+}
+
+.react-flow__node-default {
+  background: #ff6060;
+}
+
+.react-flow__node-input {
+  background: #9999ff;
+}
+
+.react-flow__node-output {
+  background: #55dd99;
+
 }
 
 .react-flow__nodesselection {
@@ -196,4 +193,4 @@
     top: 50%;
     transform: translate(0, -50%);
   }
-}
+}