Details
Description
Bootstrap 4 stables uses nested calc() values in CSS.
For example:
calc((0.5rem + 1px) * -1);
The php-css-parser has issues processing these values for a number of reasons.
Addition inside calc is not support
Nested values are not supported
As a result the php-css-parser strips out these calc values and bootstrap 4 components like popovers do not have correctly styled arrows