function transform(node) {
    var _valueParser = (0, _postcssValueParser2.default)(node.value),
        nodes = _valueParser.nodes;

    if (nodes.length === 1) {
        return;
    }
    var match = getMatch(nodes.filter(_evenValues2.default).map(function (n) {
        return n.value;
    }));
    if (match.length) {
        node.value = match[0][0];
    }
}
Specification: https://drafts.csswg.org/css-display/#the-display-properties