React landing page template

I am developing a startup and I need a responsive React landing page template that fits tablets, mobile and desktops. There is no design template, you can base yourself on a IT service/product landing page and all texts "lorem ipsum". The source code is more important than design here. The code must be clean and readable, it must follow the best React design patterns. We want to have only functional based components and if possible TypeScript, max of 5 props per component. The landing page template must have the sections as follow: 1 - Message box on top of the page with option to be closed; 2 - Menubar with 4 menus up to 8, menus may have the dropdown possibility, with more inner menus within it. It should be a component, dev team will decide when use it; 3 - Logo space on top, we need two different implementations: a - logo inside the menubar when the menubar is used; b - lonely logo on top when the menubar is not used; 4 - Testimonials section; 5 - Price section; 6 - Trusted by section; 7 - Text and image sections; It’s important to have in mind that any section we add to the page must be place automatically placed “in the stack” without much problems, for example: 
<MainContainer>
 <MenuBar /> 
<MainSection />
 <TestimonialSection />
 <PriceSection />
 <ContactMeSection />
 <AnySession />
 <AnySession />
 < … />
 </ MainContainer> And no matter how many sections we add to the page, they all may fit well.

 We don’t want to use Bootstrap or JQuery, we require pure CSS. We don’t want to use any ready to use components like Material Design or whatever.
 
The code must be well documented in order to easily create new themes, change font family, button and text colors. The freelancers must be available to implement future projects and maintain the code. All references regarding to the mentioned sections are attached.