Multisite isn’t really the best option here.
If you need different layouts and styles for, say, the header on different pages, you can use the is_page function to call a different header file depending on which page the user is on.
So to load up a different header on your home page as opposed to any other page, in your index.php (or other page template) add: if ( is_page('home') ) { echo get_header(home) }
In this case you’d need a file called “header-home.php” that contains all the necessary code for that custom header, with any classes/id’s for items specific to that page so you can style them appropriately.
If you want a quick and easy (but not technically correct) way of doing it, you can just wrap some inline styles in an is_page function, so that those styles are only applied if a user is on that page. But if it were me I’d just load up custom template files to avoid inline styling.