BMI calculator example (#130)

bmi_calculator/lib/calculator/calculate_button.dart

@@ -0,0 +1,38 @@
+import 'package:flutter/material.dart';
+
+import '../palette.dart';
+
+class CalculateButton extends StatelessWidget {
+  const CalculateButton({
+    super.key,
+    required this.onTap,
+  });
+
+  final VoidCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      height: MediaQuery.of(context).size.height / 12,
+      width: double.infinity,
+      decoration: BoxDecoration(
+        borderRadius: BorderRadius.circular(5),
+        color: Palette.action,
+      ),
+      child: TextButton(
+        style: ButtonStyle(
+          overlayColor:
+              MaterialStateProperty.all(Colors.white.withOpacity(0.10)),
+        ),
+        onPressed: onTap,
+        child: const Text(
+          'CALCULATE YOUR BMI',
+          style: TextStyle(
+            color: Palette.textActive,
+            fontSize: 20,
+          ),
+        ),
+      ),
+    );
+  }
+}