- Codecademy - HTML & CSS https://www.codecademy.com/catalog/language/html-css
- A free guide to elements https://gethead.info/
- Single Responsibility by Drew Barontini https://drewbarontini.com/articles/single-responsibility-principle/
- Philip Walton: Container Queries | CSSconf EU 2018 https://www.youtube.com/watch?v=0wA4CMo9_EU
- Mark Dalgleish: A Unified Styling Language (React, React Native, Styled Components, Design Systems etc.) https://www.youtube.com/watch?v=X_uTCnaRe94
- CSS Grid Playground - Firefox Devtools - Introduction to CSS Grid Layout https://mozilladevelopers.github.io/playground/css-grid/
- 30 Seconds of CSS https://github.com/30-seconds/30-seconds-of-css
- CSS Reference - A free visual guide to CSS https://cssreference.io/
- Responsive Components: a Solution to the Container Queries Problem https://philipwalton.com/articles/responsive-components-a-solution-to-the-container-queries-problem/
- CSS Blocks — Blazing fast CSS for your design systems and app components http://css-blocks.com/
- A Complete Guide to Grid https://css-tricks.com/snippets/css/complete-guide-grid/
- CSS Grid — Learn all about CSS Grid with Wes Bos in this free video series https://cssgrid.io/
- In defense of Functional CSS https://www.mikecr.it/ramblings/functional-css/
- Tailwind — A utility-first CSS framework for rapidly building custom user interfaces https://tailwindcss.com/docs/what-is-tailwind/
- Tachyons — Create fast loading, highly readable, and 100% responsive interfaces with as little css as possible https://tachyons.io/
- Semantic UI — User Interface is the language of the web https://semantic-ui.com/
- Painting with Code - Introducing our new open source library React Sketch.app https://airbnb.design/painting-with-code/
- ReactSketch.app - render React components to Sketch; tailor-made for design systems http://airbnb.io/react-sketchapp/
- Bit - Components are building blocks. You are the architect. https://bitsrc.io/
- Custom Elements Everywhere — Making sure frameworks and custom elements can be BFFs https://custom-elements-everywhere.com/
- Front-End Performance Checklist 2019 https://www.smashingmagazine.com/2019/01/front-end-performance-checklist-2019-pdf-pages/
- What happens when you visit ft.com? https://medium.com/ft-product-technology/making-a-request-to-the-financial-times-b2119a2f422d
- React Performance Fixes on Airbnb Listing Pages https://medium.com/airbnb-engineering/recent-web-performance-fixes-on-airbnb-listing-pages-6cd8d93df6f4
- A Pinterest Progressive Web App Performance Case Study https://medium.com/dev-channel/a-pinterest-progressive-web-app-performance-case-study-3bd6ed2e6154
- Phoenix performance metrics within the browser developer tools https://blog.dnsimple.com/2018/02/server-timing-with-phoenix/
- Optimize Website Speed With Chrome DevTools https://developers.google.com/web/tools/chrome-devtools/speed/get-started
- A Modern Front-End Workflow with DevTools - Umar Hansa https://www.youtube.com/watch?v=wz1Sy5C039M