When the iPhone X came out with the infamous notch, you may have heard of the new
safe-area-inset values, which allowed browsers to detect the area of the screen that was covered by the notch and move content around appropriately.
Recently, these values have been formalised as part of a new specification for CSS Environment Variables. This specification is still in the stage of Editor’s Draft which means that, although some browsers may begin implementation, it is not yet an official part of the specification. However, it does have good support with browsers that need it, e.g. iOS Safari on the iPhone X, and can be used in a progressive way.
... read the whole story at bitsofco.de.