I'd recommend just using plain JavaScript. There's a great blog article by Githubs engineering team about how they removed Jquery from their front-end and now rely just on vanilla JavaScript: https://githubengineering.com/removing-jquery-from-github-fr...

Also, don't be afraid of embracing multi page app versus going for a single page app (they're largely overrated).

For front end CSS design framework, I'd recommend something like Bulma. Very easy, modern and CSS-only. You can learn it all in less than an hour.