body { counter-reset: ch2 ch3 ch4; }
    h2 { counter-increment: ch2; counter-set: ch3 0 ch4 0; } 
    h3 { counter-increment: ch3; counter-set: ch4 0; } 
    h4 { counter-increment: ch4; } 
    h2::before { content: counter(ch2,decimal) ". "; }
    h3::before { content: counter(ch2,decimal) "." counter(ch3,decimal) " "; }
    h4::before { content: counter(ch2,decimal) "." counter(ch3,decimal) "." counter(ch4,decimal) " "; }