content [nfc]: Add ContentTheme.colorGlobalTimeBorder

The dark and light values come from the web app.

This completes the sweep through message-content colors for #95 dark
theme. They are all either in ContentTheme with light/dark variants,
or still inline but with a comment explaining that they don't need
light/dark variants.

Author: chrisbobbe

lib/widgets/content.dart

@@ -37,6 +37,7 @@ class ContentTheme extends ThemeExtension<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(),
+      colorGlobalTimeBorder: const HSLColor.fromAHSL(1, 0, 0, 0.8).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(),
@@ -61,6 +62,7 @@ class ContentTheme extends ThemeExtension<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(),
+      colorGlobalTimeBorder: const HSLColor.fromAHSL(0.4, 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(),
@@ -86,6 +88,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
     required this.colorCodeBlockBackground,
     required this.colorDirectMentionBackground,
     required this.colorGlobalTimeBackground,
+    required this.colorGlobalTimeBorder,
     required this.colorMathBlockBorder,
     required this.colorMessageMediaContainerBackground,
     required this.colorThematicBreak,
@@ -110,6 +113,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
   final Color colorCodeBlockBackground;
   final Color colorDirectMentionBackground;
   final Color colorGlobalTimeBackground;
+  final Color colorGlobalTimeBorder;
   final Color colorMathBlockBorder; // TODO(#46) this won't be needed
   final Color colorMessageMediaContainerBackground;
   final Color colorThematicBreak;
@@ -160,6 +164,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
     Color? colorCodeBlockBackground,
     Color? colorDirectMentionBackground,
     Color? colorGlobalTimeBackground,
+    Color? colorGlobalTimeBorder,
     Color? colorMathBlockBorder,
     Color? colorMessageMediaContainerBackground,
     Color? colorThematicBreak,
@@ -174,6 +179,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
       colorCodeBlockBackground: colorCodeBlockBackground ?? this.colorCodeBlockBackground,
       colorDirectMentionBackground: colorDirectMentionBackground ?? this.colorDirectMentionBackground,
       colorGlobalTimeBackground: colorGlobalTimeBackground ?? this.colorGlobalTimeBackground,
+      colorGlobalTimeBorder: colorGlobalTimeBorder ?? this.colorGlobalTimeBorder,
       colorMathBlockBorder: colorMathBlockBorder ?? this.colorMathBlockBorder,
       colorMessageMediaContainerBackground: colorMessageMediaContainerBackground ?? this.colorMessageMediaContainerBackground,
       colorThematicBreak: colorThematicBreak ?? this.colorThematicBreak,
@@ -195,6 +201,7 @@ class ContentTheme extends ThemeExtension<ContentTheme> {
       colorCodeBlockBackground: Color.lerp(colorCodeBlockBackground, other.colorCodeBlockBackground, t)!,
       colorDirectMentionBackground: Color.lerp(colorDirectMentionBackground, other.colorDirectMentionBackground, t)!,
       colorGlobalTimeBackground: Color.lerp(colorGlobalTimeBackground, other.colorGlobalTimeBackground, t)!,
+      colorGlobalTimeBorder: Color.lerp(colorGlobalTimeBorder, other.colorGlobalTimeBorder, t)!,
       colorMathBlockBorder: Color.lerp(colorMathBlockBorder, other.colorMathBlockBorder, t)!,
       colorMessageMediaContainerBackground: Color.lerp(colorMessageMediaContainerBackground, other.colorMessageMediaContainerBackground, t)!,
       colorThematicBreak: Color.lerp(colorThematicBreak, other.colorThematicBreak, t)!,
@@ -1126,7 +1133,6 @@ class GlobalTime extends StatelessWidget {
   final GlobalTimeNode node;
   final TextStyle ambientTextStyle;
 
-  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
 
   @override
@@ -1140,7 +1146,7 @@ class GlobalTime extends StatelessWidget {
       child: DecoratedBox(
         decoration: BoxDecoration(
           color: contentTheme.colorGlobalTimeBackground,
-          border: Border.all(width: 1, color: _borderColor),
+          border: Border.all(width: 1, color: contentTheme.colorGlobalTimeBorder),
           borderRadius: BorderRadius.circular(3)),
         child: Padding(
           padding: const EdgeInsets.symmetric(horizontal: 0.2 * kBaseFontSize),