Is the salary lawful or unlawful, given that the work involves computers and networking at "Carrefour Egypt," which sells prohibited goods, knowing that the tasks include printing papers for both prohibited and lawful products, assisting in their inventory, and sometimes acting as an accountant for them?

The safest course for a Muslim is not to work in shops that sell both lawful and unlawful items. If one needs to work in such a place, it is not permissible for him to sell unlawful items or assist in their sale in any way. Placing price tags on prohibited products is considered assisting in their sale, and Allah Almighty says: ﴿And cooperate not in sin and aggression﴾ (Al-Ma'idah: 2). If the work necessitates engaging in what the Shari'ah has forbidden, then it is obligatory to leave it, and whoever gives up something for the sake of Allah, Allah will compensate him with something better.