revamp new trip flow

frontend/lib/constants.dart

@@ -1,6 +1,64 @@
+import 'package:flutter/material.dart';
+
 const String APP_NAME = 'AnyWay';
 
 String API_URL_BASE = 'https://anyway.anydev.info';
 String PRIVACY_URL = 'https://anydev.info/privacy';
 
 const String MAP_ID = '41c21ac9b81dbfd8';
+
+
+const Color GRADIENT_START = Color(0xFFF9B208);
+const Color GRADIENT_END = Color(0xFFE72E77);
+
+const Color PRIMARY_COLOR = Color(0xFFF38F1A);
+
+ThemeData APP_THEME = ThemeData(
+  primaryColor: PRIMARY_COLOR,
+
+  scaffoldBackgroundColor: Colors.white,
+  cardColor: Colors.white,
+  useMaterial3: true,
+
+  colorScheme: ColorScheme.light(
+    primary: PRIMARY_COLOR,
+    secondary: GRADIENT_END,
+    surface: Colors.white,
+    error: Colors.red,
+    onPrimary: Colors.white,
+    onSecondary: const Color.fromARGB(255, 30, 22, 22),
+    onSurface: Colors.black,
+    onError: Colors.white,
+    brightness: Brightness.light,
+  ),
+
+
+  textButtonTheme: TextButtonThemeData(
+    style: TextButton.styleFrom(
+      backgroundColor: PRIMARY_COLOR,
+      textStyle: TextStyle(
+        color: Colors.black,
+      ),
+    ),
+  ),
+
+  iconButtonTheme: IconButtonThemeData(
+    style: ButtonStyle(
+      backgroundColor: MaterialStateProperty.all(PRIMARY_COLOR),
+    )
+  ),
+  
+  buttonTheme: ButtonThemeData(
+    buttonColor: PRIMARY_COLOR,
+    textTheme: ButtonTextTheme.primary,
+  ),
+
+  
+);
+
+
+const Gradient APP_GRADIENT = LinearGradient(
+  begin: Alignment.topLeft,
+  end: Alignment.bottomRight,
+  colors: [GRADIENT_START, GRADIENT_END],
+);