1. For the translation, you have to use the Loco translate plugin and translate the theme and core plugin files on your site as per your requirements.
Please read this article – https://xstore.helpscoutdocs.com/article/30-base-theme-translation and create a translation for the XStore theme. Make sure that translation files are placed in /wp-content/languages/themes/ folder.
About XStore Core plugin translation, you need to Sync it – https://xstore.helpscoutdocs.com/article/103-translation-files-update , then find and translate new strings. Also, synchronize translation for WooCommerce plugin.
2. For the Text color white issue, Could you please share your site WP Admin URL and Credentials with me in the private content area of this topic, so that I’ll check and help you out further? Please share the page URL as well as having this issue.
Regards 8Themes Team.