Website development (adaptive design, adaptive content)

The existing website should be improved:
(1) Adaptive design. Traditionally: for a laptop, for a large-format display, for a tablet and for a phone.
2) Set up responsive content: depending on the keywords that the user uses to access the site, he sees different content of the site (some sections are hidden from it).
(3) Add new sections to the site. To douse the content.
(4) Place the link “Add to favorites” to automatically add the site to the favorites of the user.
Your price and examples of work, please.