Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
cdnjs is a free distributed JS library delivery service.
LiteSpeed is a high-scalability web server.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.
PHP is a general-purpose scripting language used for web development.
Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.
Swiper is a JavaScript library that creates modern touch sliders with hardware-accelerated transitions.
Unpkg is a content delivery network for everything on npm.