Add another repeating-linear-gradient below the one you just added. Give it a 90deg direction, use your building color from 0% to 12% and window color 12% to 44%. This will make a bunch of rectangle windows."
After the second “repeating-linear-gradient” text you have put ‘()’. Use just an opening parenthesis ‘(’ . Then, delete the closing parenthesis ‘),’ after the second “repeating-linear-gradient”. And close your previous “repeating-linear-gradient” with ‘),’ .