就算 (jiù suàn) is a colloquial conjunction meaning 'even if, granted that' — it introduces a hypothetical concession and is common in everyday speech. Compared to 即使 (jí shǐ), which is neutral and used in both speech and writing, 就算 feels more casual and can carry a tone of 'even if we admit that'. 哪怕 (nǎ pà) is similarly colloquial but emphasizes 'no matter how' with a stronger concessive force.