@mixin cq-prolyfill($query) {
    &#{cq-prolyfill($query)} {
        @content;
    }
}

@function cq-prolyfill($query) {
    @return unquote(".\\:container\\(" + cq-prolyfill-escape(cq-prolyfill-strip-spaces(to-lower-case($query))) + "\\)");
}

@function cq-prolyfill-add-backslash($string, $search) {
    $index: str-index($string, $search);
    @while $index {
        $string: str-insert($string, '\\', $index);
        $newIndex: if(
            str-length($string) < $index + 2,
            null,
            str-index(str-slice($string, $index + 2), $search)
        );
        $index: if($newIndex, $index + 1 + $newIndex, null);
    }
    @return $string;
}

@function cq-prolyfill-remove($string, $search) {
    $index: str-index($string, $search);
    @while $index {
        $string: str-slice($string, 1, $index - 1) + str-slice($string, $index + 1);
        $index: str-index($string, $search);
    }
    @return $string;
}

@function cq-prolyfill-escape($string) {
    @each $char in '[' ']' '!' '"' '#' '$' '%' '&' "'" '(' ')' '*' '+' ',' '.' '/' ':' ';' '<' '=' '>' '?' '@' '^' '`' '{' '|' '}' '~' {
        $string: cq-prolyfill-add-backslash($string, $char);
    }
    @return $string;
}

@function cq-prolyfill-strip-spaces($string) {
    // tab, line feed, carriage return and space
    $chars: "\9\a\d\20";
    @for $i from 1 through str-length($chars) {
        $string: cq-prolyfill-remove(
            $string,
            str-slice($chars, $i, $i)
        );
    }
    @return $string;
}