main {
    counter-reset: h1;
}

h1 {
    counter-reset: h2;
}

h2 {
    counter-reset: h3;
}

h3 {
    counter-reset: h4;
}

h1:before {
    counter-increment: h1;
    content: counter(h1) ". ";
}

h2:before {
    counter-increment: h2;
    content: counter(h1) "." counter(h2) ". ";
}

h3:before {
    counter-increment: h3;
    content: counter(h1) "." counter(h2) "." counter(h3) ". ";
}

h4:before {
    counter-increment: h4;
    content: counter(h1) "." counter(h2) "." counter(h3) "." counter(h4) ". ";
}