primary header / color

Hello, it's strange, I notice that on the primary menu, when I'm on the chantillynegra.fr site I notice that when I'm on the shop for example, the "shop" link on the menu doesn't have the color highlight. I don't know what to do and I don't understand why I don't have the highlighting. Normally, when I'm on the blog page, the blog label on the main menu should be highlighted in color to indicate that I'm on the page. Best regards