Design & Build an exclusive online auction platform

Design & build exclusive online live auction platform that is user friendly with simple and attractive design. The sellers are industry specific and will sell rights for sponsorship for sport venues and athletes including digital rights and pitch banners. Seller must have a state of art dashboard, where will be able to promote it's offered product, invite specific bidders by email (several levels of profile), upload short video and any other format that can support his/her cause - contracts etc. Sellers will offer season shirt/jersey branding (tangible sponsorship), but also intangibles (social media hits, etc). Sellers must have an option of promoting its auction on social medias / boost industry (country specific) audience etc. Billing system must incorporate major credit cards / paypal and also pre-paid systems and large payment providers. Platform needs to be ready to be plugged in to a web-shop that will be created later as a separate project, but needs to ready to connect. BEWARE - only logo and name will be provided and it is required to design the modern, minimalistic and attractive landing page and provide a simple png/jpg example before the contract will be awarded. Admin interface and also user's dashboard as well as sellers as bidders is a must be for final review and milestone release. Delivery time of full product will be one of the decisive factors (15 days maximum limit) Google analytics connection as well as easy social media promotion and profile creation for sellers is crucial condition for finishing the project.