Modernize B2B Marketplace, Add Features

My B2B marketplace runs smoothly on a custom PHP full-stack codebase, but its look and several key flows feel dated. With all the guide snippets and reference links ready for you, I want to complete a... (Budget: $200 - $350 USD, Jobs: CSS3, Full Stack Development, Graphic Design, HTML, HTML5, JavaScript, Mobile App Development, PHP, Web Development, Website Design)