You can use the Dark Reader extension for Firefox on computers & Android, which makes all sites dark, or the Stylus extension which allows you to load custom si

You can use the Dark Reader extension for Firefox on computers & Android, which makes all sites dark, or the Stylus extension which allows you to load custom site-specific stylesheets. Stylus allows access to a big repository of community-made themes and there are surely some dark ones for HN. These both are likely also available for Chrome.