In CSS, you can set an element’s border to 0.5 pixels. How does that even work?

Question

In CSS, you can set an element’s border to 0.5 pixels. How does that even work?

In: 2

Answer 1

Interpolation. If the border is #000 and the pixel where half of the border is supposed to be is #fff, the pixel color will be in between both.

Also there’s a lot of devices that have more dense displays (phones, tablets, higher end laptops…) and don’t map pixels 1:1.