UI nit picks

example/lib/neumorphic_button.dart

@@ -1,50 +1,38 @@
 import 'package:flutter/material.dart';
 
-extension ColorUtils on Color {
-  Color mix(Color another, double amount) {
-    return Color.lerp(this, another, amount);
-  }
-}
-
 class NeumorphicButton extends StatelessWidget {
   final Widget child;
   final Color backgroundColor;
-  final EdgeInsets margin;
-  final EdgeInsets padding;
 
   const NeumorphicButton({
     Key key,
     @required this.child,
     this.backgroundColor = Colors.white,
-    this.margin = const EdgeInsets.all(8),
-    this.padding = const EdgeInsets.all(14),
   }) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
     return Container(
       child: child,
-      margin: margin,
-      padding: padding,
+      margin: EdgeInsets.all(8.0),
+      height: 40,
+      width: 40,
       decoration: BoxDecoration(
-        shape: BoxShape.circle,
         color: backgroundColor,
-        gradient: LinearGradient(
-            begin: Alignment.topLeft,
-            end: Alignment.bottomRight,
-            colors: [
-              backgroundColor.mix(Colors.white, 0.2),
-              backgroundColor.mix(Colors.black, 0.1),
-            ]),
+        shape: BoxShape.circle,
         boxShadow: [
           BoxShadow(
-            blurRadius: 1,
-            color: backgroundColor.mix(Colors.white, 0.6),
+            color: Colors.grey[700],
+            offset: Offset(0, 1.0),
+            blurRadius: 0.5,
+            spreadRadius: 0,
           ),
           BoxShadow(
-            blurRadius: 1,
-            color: backgroundColor.mix(Colors.black, 0.3),
-          )
+            color: Colors.white,
+            offset: Offset.zero,
+            blurRadius: 0.5,
+            spreadRadius: 0,
+          ),
         ],
       ),
     );