Hello, and welcome to CSS Hell, where you will be subjected to 15 unimaginably torturous CSS puzzles. "What did I do to deserve this?", you ask. But you know perfectly well: you blashpemized Cascading Style Sheets. I saw that time your friends were complaining about CSS and you piled on with "CSS isn't even a real programming language"

• CSS Hell @ GitHub.

Become a better frontend developer.

Take your frontend skills to the next level by recreating real websites from real companies.

The perfect type of practice for developers of all skill levels. Are you up for the challenge?

leetcode but better. Head-to-head coding battle with magic.

Advent of Docker is a 24-day challenge to learn Docker, created by the Founders (Jonas and Lukas) of Sliplane.

Advent of Docker is an educational initiative designed to make learning Docker fun and accessible. Each day in December leading up to Christmas, we release a new Docker challenge or tutorial. The format is inspired by the popular “Advent of Code” concept, but focused entirely on Docker and container technology.

A free, fun platform for learning cryptography.

Learn about modern cryptography by solving a series of interactive puzzles and challenges. Get to know the ciphers and protocols that secure the digital world by breaking them.

• 115 - RADIUS/UDP Considered Harmful @ Feisty Duck's Cryptography & Security Newsletter.

Project Euler is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve. Although mathematics will help you arrive at elegant and efficient methods, the use of a computer and programming skills will be required to solve most problems.