/// Mixin to provide a fallback for unsupported CSS properties
/// @param {string} $prop - the CSS property to apply
/// @param {string} $modern - the modern CSS value to apply
/// @param {string} $fallback - the fallback CSS value to apply
/// @output CSS property with fallback for unsupported browsers
@mixin ds_unsupported-css-fallback($prop, $modern, $fallback) {
    #{$prop}: #{$fallback};
    #{$prop}: $modern;
}