Landlord deducting insane amounts from security deposit

[Sam Smith]

I just moved out of a Chicago apartment (1 bedroom). The apartment was handed over to the owner after a walkthrough where I handed the keys to the LL and we identified 2-3 issues such as crayon marks on walls and kitchen cabinets. There was no written document of issues identified. the LL has deducted 1.2 times the rent from the security deposit - $1050. and I do not agree with all the items he has listed.

My questions are:

1. can I be held liable for problems not identified during the walkthrough at the time of apartment handover?
2. is there a limit on the amount the Landlord can deduct from the security deposit for a 1 bedroom apartment?
3. Can I go to a small claims court even though there is nothing in written as to what was agreed during the handover?
4. The LL has sent a list of corrections he had to do, but the expenses are not broken with each item. Is he required to give a breakdown?