It's still in draft, and not supported anywhere yet, but I'm wondering if esbuild should handle this code when minifiying:

.link {
    color: red;
    &:hover {
      color: blue;
    }
}
.another-class {
    color: yellow;
}

Right now, this outputs:

.link{color:red;&:hover{color:#00f}}.another-class{color:#ff0}

One day, this will be supported in browsers. But for now, we'd want to output this if our CSS target isn't set to the newest support:

.link{color:red}.link:hover{color:#00f}.another-class{color:#ff0}

Or even:

.link{color:red}.another-class{color:#ff0}

Or maybe minification should fail (similar to JS when your syntax cannot be minified to support your target)?