In preprocessors, like SASS, you can use negative values like:
$margin-md: 10px;
.class {
margin-bottom: -$margin-md;
}
How do I do this using custom properties?
// This doesn't work
.class {
margin-bottom: -var(--margin-md);
}
As of this posting, March 2018, the only way to use negative custom properties is by multiplying it by -1
with the calc function.
// Vanilla CSS
.class {
margin-bottom: calc(var(--margin-md) * -1);
}
If you're using a preprocessor with custom properties, you'll need to escape the custom property within the calc function.
// SASS
.class {
margin-bottom: calc(#{var(--margin-md)} * -1);
}