The tabs are quite easy to use as they don't need absolute positioning and min-heights.
They can also be used multiple times in one document without any influence on CSS.
Unfortunately, these tabs have one downside: limited tab count. The limit is set in the CSS (see comments in the CSS code). But let's get real: who uses lots of tabs?
And one more thing: no animation to prevent annoying page jumps.
Have an improvement idea? Feel free to suggest it in the comments!