Update app.py

app.py

@@ -333,11 +333,13 @@ function draw() {
         const offset = Math.max(40, radius*0.28 + len*0.12);
         const ux = mx/len, uy = my/len;
         loopGroup.append("path")
-            .attr("d", `M${sa.x},${sa.y} Q${mx+ux*offset},${my+uy*offset} ${sb.x},${sb.y}`)
+            .attr("d", path)
             .attr("fill", "none")
-            .attr("stroke", "#227a6d")
-            .attr("stroke-width", 2.8)
-            .attr("opacity", 0.95);
+            .attr("stroke", "#9b59b6")          // bright violet
+            .attr("stroke-width", 4.5)          // thicker so stands out
+            .attr("opacity", 1)
+            .attr("stroke-linecap","round")
+            .attr("stroke-linejoin","round");
     });
 
     // --------------------------------------------------------------