I'm working with a javascript library x-spreadsheet and importing it for browser use. During the import it requests a file src/index.less. On the browser console I am getting the error: "Uncaught SyntaxError: Invalid or unexpected token (at index.less:1:1)" Inspecting the file doesn't show any strange characters at that position. I also inspected what my browser received and nothing looks odd:

@css-prefix: x-spreadsheet;
// color
@red-color: #DB2828;
@red-hover-color: #d01919;
@orange-color: #F2711C;

This is my first time working with a .less file. What am I missing here?