build a simple secure Dapp with escrow concept for seller and buyers

build a secure Dapp that allow people to make a deals using escrow concept and cryptocurrencies like BTC , and usdt,. The seller party has the ability to write down his services, milestones, and charges. once the buyer accept it, the amount in his wallet will be held by the platform until the buyer confirm he received the services. must has easy to use front-end mobile app and solid secure back-end