Refers to the fine points or specific parts of something, often used when examining or explaining something thoroughly.
He's a person who is particular about the details of his work.
Let's discuss the details of the plan.
彼は細部にまで注意を払う。
He pays attention to the smallest details.
I explained the plan down to every detail.
I checked the details of the contract before signing.
The designer finished the piece paying attention to every last detail.
ディテール is a casual loanword often used for artistic or design details, while 細部 is the standard Japanese word usable in any formal or technical context.
全体 refers to the whole of something, in direct contrast to 細部, which refers to its small individual parts.
Compound of 細 (さい, 'fine, minute') and 部 (ぶ, 'part, section').