Why is the em() function not working in sass?

Question

css

Hello, I write a line like this:
font-size: em(20px)
I get the same output. Tell me what I'm doing wrong or maybe something is not connected?
Otherwise, sass works, the code compiles.
Thanks in advance to all who respond

Answer 1

Because you need to write a mixin:

$browser-context: 16; // Default

@function em($pixels, $context: $browser-context) {
  @return #{$pixels/$context}em;
}

Call without specifying px for pixels.

Answer 2

sass doesn't have built-in function em
em was good to use for IE6-7