Chances are if you're a web developer you're going to have to write some CSS from time to time. When you first looked at CSS it probably seemed like a breeze. You added some border here, changed some colors there. JavaScript was the hard part of front end development! Somewhere during your progression as a front end developer that changed though! What's worse is that many developers in the front end community have simply learned to dismiss CSS as a toy language. The truth however is that when we hit a wall many of us don’t actually understand what our CSS is doing under the hood! We all like to make jokes about it, but how many of us have actually taken the time to try and understand the CSS we're writing. How many of us have actually reasonably debugged an issue to the next lowest abstraction layer when we hit a wall? All too often we settle for the first StackOverflow answer, hacks, or we just let the issue go entirely. In this talk we're going to finally take a step back and stop mindlessly throwing darts at the dart board! We’ll discuss the most common issues developers face such as, z-index, the cascade, and positioning in depth by diving deep into the browser's internal rendering engine structure to see how are styles are actually parsed. Sure, you may still not have an eye for design, but you might just walk away a CSS guru!