Quick Answer: 375mm length, 75mm thick (60mm or less recommended for best cooling)
Thorough Answer: We typically don't recommend moving forward with graphics cards thicker than 60mm to ensure our users can maintain good airflow inside the case. Cards larger than 60mm puts clearance between the glass and GPU fans around ~15mm or less and could put your card at risk of overheating despite having additional help from the bottom fans.
If you're interested in using a card larger than 60mm, we have seen some of our users opting to use a 3rd party riser cable/bracket combination to combat the thickness of the recent 40 Series cards and new 7900 xtx. The product will be able to let you move GPU closer to the motherboard and allow the GPU to breathe and avoid thermal throttling! We'll link the product and reference from reddit down below.
Reddit Post Example: 4090 Y60 build : Hyte (reddit.com)
Amazon Link: https://www.amazon.com/EZDIY-FAB-US-4-0CM-AGPU-B/dp/B096MC685G
We hope this helps with your decision. If you have any other questions or concerns, please do not hesitate to reach out.