douchebag way of vertical alignment

douchebag-vertical-align.css

.element {
  position: relative;
  top: 50%;
  transform: translateY(-50%);
}

This works well a lot of the time, but just be aware that since css transforms are performed on layers on the GPU, the calculations it returns will not necessarily land on even pixels. When that happens you're going to get blurry text and edges.

If you know the height of the element you're centering, it's better to use a negative top margin that is half the height. That will always round to the nearest pixel. Or just cave and use flexbox 😄

To prevent the half-pixel issue, set this on the parent element:

  transform-style: preserve-3d;