srs/lib/core/theme.dart

import 'package:flutter/material.dart';

class C {
  static const bg = Color(0xFFF4F2EC);
  static const outer = Color(0xFFE7E4DB);
  static const ink = Color(0xFF1F2A2E);
  static const muted = Color(0xFF5E6C71); // 4.9:1 on bg, 5.4:1 on white
  static const navy = Color(0xFF1B2A49);
  static const navyDeep = Color(0xFF101B33);
  static const chip = Color(0xFFE1E6F0);
  static const green = Color(0xFF2F7656); // 5.5:1 on white, 4.7:1 on greenTint
  static const greenTint = Color(0xFFE3F1EA);
  static const gold = Color(0xFFD4A64A);
  static const goldTint = Color(0xFFF7EBD0);
  static const goldText = Color(0xFF735614); // 5.4:1 on goldTint
  static const border = Color(0xFFE6E0D4);
  static const border2 = Color(0xFFC9CED8);
  static const placeholder = Color(0xFF7A8689); // hints and chevrons, 3.8:1
  static const softOnNavy = Color(0xFFB8C2DA);
  static const red = Color(0xFFB04A37); // 5.4:1 on white
  static const redDeep = Color(0xFF953D2C);
  static const redTint = Color(0xFFFBE9E5);
  static const white = Colors.white;
  static const hover = Color(0xFFF8F7F3);
  static const focus = Color(0xFF3D5A99);

  // Overlays, shadows and disabled fills
  static const onNavy5 = Color(0x0DFFFFFF);
  static const onNavy8 = Color(0x14FFFFFF);
  static const onNavy20 = Color(0x33FFFFFF);
  static const goldSoft = Color(0x26D4A64A);
  static const goldGlow = Color(0x55D4A64A);
  static const shadowNavy = Color(0x331B2A49);
  static const shadowNav = Color(0x14101B33);
  static const disabled = Color(0xFFF0EEE8);
  static const fieldDisabled = Color(0xFFEFEDE6);
  static const skeleton = Color(0xFFECE8DF);
}

/// Width breakpoints, measured on the window, not the device.
class Bp {
  static const medium = 600.0; // rail navigation, wider gutters
  static const expanded = 1024.0; // full sidebar
  static const pageMax = 1120.0; // widest content column
  static const readMax = 760.0; // detail and form screens
}

/// Horizontal padding that keeps content in a centred column of [max] width.
double pageGutter(double width, [double max = Bp.pageMax]) {
  if (width < Bp.medium) return S.s20;
  final side = (width - max) / 2;
  return side > S.s32 ? side : S.s32;
}

/// Spacing scale (logical pixels).
class S {
  static const s2 = 2.0;
  static const s4 = 4.0;
  static const s6 = 6.0;
  static const s8 = 8.0;
  static const s10 = 10.0;
  static const s12 = 12.0;
  static const s14 = 14.0;
  static const s16 = 16.0;
  static const s18 = 18.0;
  static const s20 = 20.0;
  static const s22 = 22.0;
  static const s24 = 24.0;
  static const s28 = 28.0;
  static const s32 = 32.0;
  static const s36 = 36.0;
}

/// Corner radii.
class R {
  static const sm = 8.0; // checkbox, handles
  static const md = 12.0; // chips, tiles
  static const input = 14.0; // fields, small cards
  static const button = 16.0;
  static const card = 18.0;
  static const dialog = 24.0;
  static const hero = 28.0; // hero cards, sheets
  static const pill = 99.0;
}

TextStyle ts(
  double size, {
  FontWeight w = FontWeight.w500,
  Color c = C.ink,
  double? h,
  double? ls,
}) => TextStyle(
  fontFamily: 'Inter',
  fontSize: size,
  fontWeight: w,
  color: c,
  height: h,
  letterSpacing: ls,
  // Tabular figures keep ticket counts, endings and rupee amounts aligned.
  fontFeatures: const [FontFeature.tabularFigures()],
);

const w4 = FontWeight.w400;
const w5 = FontWeight.w500;
const w6 = FontWeight.w600;
const w7 = FontWeight.w700;

ThemeData buildTheme() {
  final scheme =
      ColorScheme.fromSeed(
        seedColor: C.navy,
        brightness: Brightness.light,
      ).copyWith(
        primary: C.navy,
        onPrimary: Colors.white,
        surface: C.bg,
        error: C.red,
      );
  return ThemeData(
    useMaterial3: true,
    fontFamily: 'Inter',
    colorScheme: scheme,
    scaffoldBackgroundColor: C.bg,
    splashFactory: NoSplash.splashFactory,
    highlightColor: Colors.transparent,
    hoverColor: C.hover,
    focusColor: C.chip,
    tooltipTheme: TooltipThemeData(
      waitDuration: const Duration(milliseconds: 500),
      textStyle: ts(12, w: w5, c: Colors.white),
      decoration: BoxDecoration(
        color: C.navyDeep,
        borderRadius: BorderRadius.circular(R.sm),
      ),
    ),
    textSelectionTheme: const TextSelectionThemeData(cursorColor: C.navy),
    snackBarTheme: SnackBarThemeData(
      behavior: SnackBarBehavior.floating,
      backgroundColor: C.navyDeep,
      contentTextStyle: ts(13, w: w6, c: Colors.white),
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(R.input),
      ),
    ),
    dialogTheme: DialogThemeData(
      backgroundColor: Colors.white,
      surfaceTintColor: Colors.transparent,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(R.dialog),
      ),
    ),
    bottomSheetTheme: const BottomSheetThemeData(
      backgroundColor: Colors.white,
      surfaceTintColor: Colors.transparent,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(R.hero)),
      ),
    ),
  );
}