Bootstrap isn't the only JavaScript/CSS framework providing a responsive layout and useful components. We're using Bootstrap in this project because of its popularity. These frameworks are worthy of a look:
- Pure.css ( https://purecss.io/): A responsive CSS framework with an emphasis on a small code footprint.
- Picnic CSS (https://picnicss.com/): A responsive CSS framework emphasizing small size and beauty.
- Shoelace (https://shoelace.style/): A CSS framework emphasizing using future CSS, meaning it uses CSS constructs at the leading edge of CSS standardization. Since most browsers don't support those features, cssnext (http://cssnext.io/) is used to retrofit that support. Shoelace uses a grid layout system based on Bootstrap's grid.
- PaperCSS (https://www.getpapercss.com/): An informal CSS framework which looks like it was hand drawn.
- Foundation (https://foundation.zurb.com/): Self-described as the most advanced responsive frontend framework in the world.
- Base (http://getbase.org/): A lightweight modern CSS framework.
HTML5 Boilerplate (https://html5boilerplate.com/) is an extremely useful basis from which to code the HTML and other assets. It contains the current best practices for the HTML code in web pages, as well as tools to normalize CSS support and configuration files for several web servers.