Online resources to learn HTML/CSS

Code.org

Code.org® is a nonprofit dedicated to expanding access to computer science in schools and increasing participation by women and underrepresented youth. Our vision is that every student in every school has the opportunity to learn computer science, just like biology, chemistry or algebra. Code.org provides the leading curriculum for K-12 computer science in the largest school districts in the United States and Code.org also organizes the annual Hour of Code campaign which has engaged more than 15% of all students in the world. Code.org is supported by generous donors including Amazon, Facebook, Google, the Infosys Foundation, Microsoft, and many more.

Codecademy

Codecademy helps millions of learners around the world get the skills they need to succeed in today’s digital world -- all in a way that’s fun, free, and accessible anywhere. Codecademy offers an entirely new, networked approach to learning in which you interact with students across the globe, build amazing projects, and - most important - apply your skills to improve your life.

Khan Academy

Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. They tackle math, science, computer programming, history, art history, economics, and more. Their math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. They have also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.

SitePoint

SitePoint is a hub for web developers to share their passion for building incredible Internet things. Founded by Mark Harbottle and Matt Mickiewicz in 1999, SitePoint is for web professionals, by web professionals: developers, designers, programmers, product creators and entrepreneurs alike.