A bilingual site is two designs, not one translation.
If the Arabic version is a mirror of the English one, it was never designed — it was flipped.
Arabic headings run longer, sit lower and need more line height. Numbers, prices and phone numbers stay left to right inside right-to-left text. Icons with a direction have to turn; icons without one must not.
We now sketch every key page in Arabic first. The English version almost always fits afterwards; the other way round, it almost never does.