Thanks for the topic.
1. Make sure you select the language in Settings > General > Site Language.
Have you read our documentation https://xstore.helpscoutdocs.com/article/30-base-theme-translation ?
Translation files should be placed in wp-content/languages/themes/ folder with correct names (xstore-pt_BR.po and xstore-pt_BR.mo).
2. Please delete this code from custom css http://prntscr.com/jilpxq and http://prntscr.com/jilrgg
“Color for cart number label” you can set in Theme Options > General > Header Settings, “Menu background color” – Theme Options > Styling > Navigation.