Compiling negative border-radius by "0px"

Created by: endcoreAK

If i change the variable

$border-radius: .25rem !default; to $border-radius: 0px !default;

all the variables wich contain subtract like

$card-inner-border-radius: subtract($card-border-radius, $card-border-width) !default;

will result in a negative border-radius wich means an invalid property value:

.card-header:first-child { border-radius: -1px -1px 0 0; }