Is taking part of the computer courses provided by work for my own personal use considered theft and unlawful gain?

If an employee agrees with the employer on a specific wage, he is not permitted to take an additional amount, because it is considered a betrayal and taking others' money without their consent. The Prophet, peace and blessings be upon him, said: "Return the trust to the one who entrusted you, and do not betray the one who betrayed you," and "Every Muslim's blood, wealth, and honor are sacred to another Muslim." The employee can request a raise from the management, and if they agree, then there is no harm; otherwise, he is not allowed to take others' money without their consent.