What I really like about the current state of #CSS with things like grid, flexbox, relative units, etc.:
It is "describe your intent and let the browser handle the math and details". It can be complex at times, because you have to clearly express your intent, but it's also immensely powerful.
I still remember getting yelled at by so called "Art Directors" for not being able to 100% reproduce their "pixel perfect" Photoshop layouts across multiple browsers and operating systems.