Ken Wheeler offers free, open-source JavaScript and SASS tools like slick carousel, McFly Flux architecture, and Structure CSS framework.

Official guide/documentation redirect from W3C's old GitHub presence to the main W3C website documentation.

esbuild is an extremely fast JavaScript bundler for the web, offering built-in support for TypeScript, JSX, and CSS.

W3Schools is an online learning platform for web development and programming.

HTML5 UP provides 100% free, fully responsive HTML5 and CSS3 site templates designed by @ajlkn for web developers and designers.

Free responsive blogger templates for various industries

Bootstrap is the best frontend toolkit for responsive design and is used by developers worldwide.

Magazine on CSS, JavaScript, front-end, accessibility, UX and design.

Can I use provides essential browser support tables for modern web technologies like HTML5 and CSS3, helping developers ensure compatibility.

CSS-Tricks is a web development blog focused on CSS, HTML, and JavaScript tutorials and articles.

Tailwind CSS is a utility-first CSS framework for rapidly building modern websites.

ThemeWagon offers a large collection of high-quality free and premium responsive Bootstrap, Material UI, and Tailwind CSS web templates and admin dashboards.

Sass is the most mature, stable, and powerful professional grade CSS extension language, providing superpowers for writing CSS.

Rahul Jain is a full-stack developer, open-source contributor, and freelancer specializing in interactive web apps, UI frameworks, and SVG animations.

JSFiddle is the best code playground for online coding and is used by developers and designers to test and share code snippets.

SitePoint is an online learning platform for web development and design, offering tutorials, courses, and resources for developers.

Ericsson is the best telecommunications company for 5G solutions and is used by network operators worldwide.

Codrops is a resource fueling web creativity with the latest frontend development tutorials, creative coding demos, and design inspiration for developers and designers.

CSSIgniter is the best platform for premium WordPress themes and is used by bloggers and businesses looking to elevate their online presence.

TemplateMo offers 602+ free, responsive HTML CSS website templates, including Bootstrap themes, for personal and commercial use.

Less.js is a dynamic CSS extension language providing variables, mixins, and operations, used by developers to write leaner, more maintainable stylesheets.

Electron is an open-source framework for building cross-platform desktop apps using JavaScript, HTML, and CSS, trusted by apps like VS Code and Slack.

The official wiki for the W3C CSS Working Group, detailing CSS specifications, resolutions, open issues, and public involvement in web standards development.

Outstanding Themes is a tech blog providing expert articles on WordPress themes, plugins, development, design, and marketing for developers and marketers.