How to import a CSS/LESS file from another project into a LESS namespace, prefixing all imported styles.

less_namespace_import.less

/* foreign.less */
/* new file, "bridge" between imported styles and stylesheet */

#export {
    .styles() {
        @import (less) "../../other-project/css/styles.css";
    }
}

/* old file */
/* styles.less */

@import "foreign.less"

.some-container {
    #export > .styles();
}