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// In NeumorphicContainer.build > Container > BoxDecoration
// ...
gradient: LinearGradient(
  begin: Alignment.topLeft,
  end: Alignment.bottomRight,
  colors: [
    color.mix(Colors.white, .2),
    color.mix(Colors.black, .1),
  ]
),

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// In NeumorphicContainer.build > Container > BoxShadow
// Mixing with white
color: color.mix(Colors.white, .6),
// ...
// Mixing with black
color: color.mix(Colors.black, .3),
// ...

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class NeumorphicContainer extends StatelessWidget {
  // ...
  
  // New property, will store overridden color
  // if passed from outside
  final Color color;

  NeumorphicContainer({
    Key key,
    this.child,

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class NeumorphicContainer extends StatelessWidget {
  // ...
  
  // New property, will store overridden color
  // if passed from outside
  final Color color;

  NeumorphicContainer({
    Key key,
    this.child,

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// In NeumorphicApp.build > MaterialApp > ThemeData
// ...
backgroundColor: Colors.blueGrey.shade200,
scaffoldBackgroundColor: Colors.blueGrey.shade200,
dialogBackgroundColor: Colors.blueGrey.shade200,
// ...

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extension ColorUtils on Color {
  Color mix(Color another, double amount) {
    return Color.lerp(this, another, amount);
  }
}

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// In NeumorphicApp
// ...
home: Scaffold(
  // Adding some background
  backgroundColor: Colors.blueGrey.shade200,
  body: Center(
    child: NeumorphicContainer(child: Text('Neumorphic')),
  ),
)
// ...

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return Container(
  decoration: BoxDecoration(
      borderRadius: BorderRadius.circular(bevel),
      color: Colors.grey.shade200,
      boxShadow: [
        BoxShadow(
          blurRadius: bevel,
          offset: -blurOffset,
          color: Colors.white,
        ),

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// In NeumorphicContainer.build
// ...
return Container(
  decoration: BoxDecoration(
    border: Border(
      top: BorderSide(width: bevel, color: Color(0xFFFFFFFFFF)),
      left: BorderSide(width: bevel, color: Color(0xFFFFFFFFFF)),
      right: BorderSide(width: bevel, color: Color(0xFFFF000000)),
      bottom: BorderSide(width: bevel, color: Color(0xFFFF000000)),
    ),

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// In NeumorphicContainer
// ...

// New property
final double bevel;

// Also adding initializer to a constructor
const NeumorphicContainer({
  Key key,
  this.child,