Build bilingual Astro exchange landing page and brand reference

flutter/brand_palette.dart

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+// Generated brand palette reference. Optional for the Flutter application.
+// This is not an application theme: choose component styling independently.
+import 'dart:ui';
+
+abstract final class SxchngeBrand {
+  static const ink = Color(0xFF14221D);
+  static const mint = Color(0xFFC4F9CE);
+  static const lime = Color(0xFFD7FF5F);
+  static const paper = Color(0xFFF9FAF6);
+  static const muted = Color(0xFF637168);
+  static const line = Color(0xFFD9E0D8);
+  static const forest = Color(0xFF396A4B);
+  static const focus = Color(0xFF168850);
+  static const darkField = Color(0xFF25372E);
+  static const darkReceive = Color(0xFF203D2D);
+  static const sageSurface = Color(0xFFEAF0E6);
+  static const blueSurface = Color(0xFFEDF0F9);
+  static const fontFamily = 'Onest';
+}