feat: pure black theme

Closes #254

Signed-off-by: bggRGjQaUbCoE <githubaccount56556@proton.me>

lib/pages/setting/widgets/model.dart

@@ -480,6 +480,18 @@ List<SettingsModel> get styleSettings => [
         title: '主题模式',
         getSubtitle: () => '当前模式：${GStorage.themeType.description}',
       ),
+      SettingsModel(
+        settingsType: SettingsType.sw1tch,
+        leading: const Icon(Icons.invert_colors),
+        title: '纯黑主题',
+        setKey: SettingBoxKey.isPureBlackTheme,
+        defaultVal: false,
+        onChanged: (value) {
+          if (Theme.of(Get.context!).brightness == Brightness.dark) {
+            Get.forceAppUpdate();
+          }
+        },
+      ),
       SettingsModel(
         settingsType: SettingsType.normal,
         onTap: (setState) => Get.toNamed('/colorSetting'),