many UI improvements and subtle tweaks

lib/common/widgets/animatedGradientButton.dart

@@ -0,0 +1,27 @@
+import 'package:flutter/material.dart';
+import 'package:simple_animations/simple_animations.dart';
+
+class AnimatedBackground extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    final tween = MultiTrackTween([
+      Track("color1").add(Duration(seconds: 4),
+          ColorTween(begin: Colors.lightBlue, end: Colors.lightBlue[300])),
+    ]);
+
+    return ControlledAnimation(
+      playback: Playback.MIRROR,
+      tween: tween,
+      duration: tween.duration,
+      builder: (context, animation) {
+        return Container(
+          decoration: BoxDecoration(
+              gradient: LinearGradient(
+                  begin: Alignment.topCenter,
+                  end: Alignment.bottomCenter,
+                  colors: [animation["color1"], Colors.lightBlue])),
+        );
+      },
+    );
+  }
+}