a {
    background: url('http://something');
    background: url('http://some"thing');
    background: url('http://some\'thing');
    background: url('http://some\"thing');
    background: url('http://some\\"thing');
    background: url('http://some\\\'thing');
    content: counters(section_counter, '.');
    content: 'prefix';
    font-family: 'some \"convoluted font name';
    font-family: 'asdf \'convoluted font name';
    font-family: 'asdf "convoluted font name';
    font-family: 'asdf \\"convoluted font name';
    font-family: 'asdf \\\'convoluted font name';
    background: url("http://something");
    background: url("http://some'thing");
    background: url("http://some\"thing");
    background: url("http://some\'thing");
    background: url("http://some\\'thing");
    background: url("http://some\\\"thing");
    content: counters(section_counter, ".");
    content: "prefix";
    font-family: "some \'convoluted font name";
    font-family: "asdf \"convoluted font name";
    font-family: "asdf 'convoluted font name";
    font-family: "asdf \\'convoluted font name";
    font-family: "asdf \\\"convoluted font name";
}