content [nfc]: Add ContentTheme.colorGlobalTimeBackground

The dark and light values come from the web app.

Author: chrisbobbe

lib/widgets/content.dart

@@ -36,6 +36,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
     return ContentTheme._(
       colorCodeBlockBackground: const HSLColor.fromAHSL(0.04, 0, 0, 0).toColor(),
       colorDirectMentionBackground: const HSLColor.fromAHSL(0.2, 240, 0.7, 0.7).toColor(),
+      colorGlobalTimeBackground: const HSLColor.fromAHSL(1, 0, 0, 0.93).toColor(),
       colorMathBlockBorder: const HSLColor.fromAHSL(0.15, 240, 0.8, 0.5).toColor(),
       colorMessageMediaContainerBackground: const Color.fromRGBO(0, 0, 0, 0.03),
       colorThematicBreak: const HSLColor.fromAHSL(1, 0, 0, .87).toColor(),
@@ -59,6 +60,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
     return ContentTheme._(
       colorCodeBlockBackground: const HSLColor.fromAHSL(0.04, 0, 0, 1).toColor(),
       colorDirectMentionBackground: const HSLColor.fromAHSL(0.25, 240, 0.52, 0.6).toColor(),
+      colorGlobalTimeBackground: const HSLColor.fromAHSL(0.2, 0, 0, 0).toColor(),
       colorMathBlockBorder: const HSLColor.fromAHSL(1, 240, 0.4, 0.4).toColor(),
       colorMessageMediaContainerBackground: const HSLColor.fromAHSL(0.03, 0, 0, 1).toColor(),
       colorThematicBreak: const HSLColor.fromAHSL(1, 0, 0, .87).toColor().withOpacity(0.2),
@@ -81,6 +83,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
   ContentTheme._({
     required this.colorCodeBlockBackground,
     required this.colorDirectMentionBackground,
+    required this.colorGlobalTimeBackground,
     required this.colorMathBlockBorder,
     required this.colorMessageMediaContainerBackground,
     required this.colorThematicBreak,
@@ -104,6 +107,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
 
   final Color colorCodeBlockBackground;
   final Color colorDirectMentionBackground;
+  final Color colorGlobalTimeBackground;
   final Color colorMathBlockBorder; // TODO(#46) this won't be needed
   final Color colorMessageMediaContainerBackground;
   final Color colorThematicBreak;
@@ -153,6 +157,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
   ContentTheme copyWith({
     Color? colorCodeBlockBackground,
     Color? colorDirectMentionBackground,
+    Color? colorGlobalTimeBackground,
     Color? colorMathBlockBorder,
     Color? colorMessageMediaContainerBackground,
     Color? colorThematicBreak,
@@ -166,6 +171,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
     return ContentTheme._(
       colorCodeBlockBackground: colorCodeBlockBackground ?? this.colorCodeBlockBackground,
       colorDirectMentionBackground: colorDirectMentionBackground ?? this.colorDirectMentionBackground,
+      colorGlobalTimeBackground: colorGlobalTimeBackground ?? this.colorGlobalTimeBackground,
       colorMathBlockBorder: colorMathBlockBorder ?? this.colorMathBlockBorder,
       colorMessageMediaContainerBackground: colorMessageMediaContainerBackground ?? this.colorMessageMediaContainerBackground,
       colorThematicBreak: colorThematicBreak ?? this.colorThematicBreak,
@@ -186,6 +192,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
     return ContentTheme._(
       colorCodeBlockBackground: Color.lerp(colorCodeBlockBackground, other.colorCodeBlockBackground, t)!,
       colorDirectMentionBackground: Color.lerp(colorDirectMentionBackground, other.colorDirectMentionBackground, t)!,
+      colorGlobalTimeBackground: Color.lerp(colorGlobalTimeBackground, other.colorGlobalTimeBackground, t)!,
       colorMathBlockBorder: Color.lerp(colorMathBlockBorder, other.colorMathBlockBorder, t)!,
       colorMessageMediaContainerBackground: Color.lerp(colorMessageMediaContainerBackground, other.colorMessageMediaContainerBackground, t)!,
       colorThematicBreak: Color.lerp(colorThematicBreak, other.colorThematicBreak, t)!,
@@ -1117,7 +1124,6 @@ class GlobalTime extends StatelessWidget {
   final GlobalTimeNode node;
   final TextStyle ambientTextStyle;
 
-  static final _backgroundColor = const HSLColor.fromAHSL(1, 0, 0, 0.93).toColor();
   static final _borderColor = const HSLColor.fromAHSL(1, 0, 0, 0.8).toColor();
   static final _dateFormat = DateFormat('EEE, MMM d, y, h:mm a'); // TODO(intl): localize date
 
@@ -1126,11 +1132,12 @@ class GlobalTime extends StatelessWidget {
     // Design taken from css for `.rendered_markdown & time` in web,
     //   see zulip:web/styles/rendered_markdown.css .
     final text = _dateFormat.format(node.datetime.toLocal());
+    final contentTheme = ContentTheme.of(context);
     return Padding(
       padding: const EdgeInsets.symmetric(horizontal: 2),
       child: DecoratedBox(
         decoration: BoxDecoration(
-          color: _backgroundColor,
+          color: contentTheme.colorGlobalTimeBackground,
           border: Border.all(width: 1, color: _borderColor),
           borderRadius: BorderRadius.circular(3)),
         child: Padding(