content: import 'package:flutter/material.dart';
  
  import 'package:niku/widget/niku.dart';
  
  class NikuScreen extends StatelessWidget {
    final Widget child;
    final Widget Function(Niku)? base;
    final Widget Function(Niku)? xs;
    final Widget Function(Niku)? sm;
    final Widget Function(Niku)? md;
    final Widget Function(Niku)? lg;
    final Widget Function(Niku)? xl;
  
    const NikuScreen({
      Key? key,
      required this.child,
      this.base,
      this.xs,
      this.sm,
      this.md,
      this.lg,
      this.xl,
    }) : super(key: key);
  
    build(context) {
      final _w = child.niku;
  
      return LayoutBuilder(
        builder: (context, constraints) {
          final width = constraints.maxWidth;
  
          if (width < 568) {
            if (base != null) return base!(_w);
  
            return child;
          }
  
          if (width < 640) {
            if (xs != null) return xs!(_w);
            if (base != null) return base!(_w);
  
            return child;
          }
  
          if (width < 720) {
            if (sm != null) return sm!(_w);
            if (xs != null) return xs!(_w);
            if (base != null) return base!(_w);
  
            return child;
          }
  
          if (width < 920) {
            if (md != null) return md!(_w);
            if (sm != null) return sm!(_w);
            if (xs != null) return xs!(_w);
            if (base != null) return base!(_w);
  
            return child;
          }
  
          if (width < 1024) {
            if (lg != null) return lg!(_w);
            if (md != null) return md!(_w);
            if (sm != null) return sm!(_w);
            if (xs != null) return xs!(_w);
            if (base != null) return base!(_w);
  
            return child;
          }
  
          if (xl != null) return xl!(_w);
          if (lg != null) return lg!(_w);
          if (md != null) return md!(_w);
          if (sm != null) return sm!(_w);
          if (xs != null) return xs!(_w);
          if (base != null) return base!(_w);
  
          return child;
        },
      );
    }
  }
  