🖼️ Add Radar Demo with custom opacity

demos/radar.html

@@ -113,6 +113,27 @@
         curve Ninja3["Ninja"] {3, 2, 1, 5, 4}
     </pre
       >
+      <pre class="mermaid">
+      ---
+      config:
+        radar:
+          axisScaleFactor: 0.25
+          curveTension: 0.1
+        theme: base
+        themeVariables:
+          cScale0: "#FF0000"
+          cScale1: "#00FF00"
+          cScale2: "#0000FF"
+          radar:
+            curveOpacity: 0
+      ---
+      radar-beta
+        title Custom colors, axisScaleFactor, curveTension, opacity
+        axis A, B, C, D, E
+        curve c1{1,2,3,4,5}
+        curve c2{5,4,3,2,1}
+        curve c3{3,3,3,3,3}
+      </pre>
     </div>
     <script type="module">
       import mermaid from '/mermaid.esm.mjs';