ol { margin-left: 0; padding-left: 1em; }
  
ol.top { counter-reset: cb cc cd; }    
ol.top>li { list-style-type: none; font-family: serif; font-size: larger; }    

ol.b { counter-reset: cc cd; }
ol.b>li { list-style-type: none;  font-size: large;}    
ol.b>li:before { counter-increment: cb; content: counter(cb) ". "; }

ol.c { counter-reset: cc cd; }
ol.c>li { list-style-type: none; font-size: medium; }    
ol.c>li:before { counter-increment: cc; content: counter(cb) "." counter(cc) ". "; }

ol.d { counter-reset: cd; }
ol.d>li { list-style-type: none; font-size: small; }    
ol.d>li:before { counter-increment: cd; content: counter(cb) "." counter(cc) "." counter(cd) ". "; }


ol.ap { counter-reset: cb cc cd; }
ol.ap li { list-style-type: none;  font-size: large; }    
ol.ap>li:before { counter-increment: cb; content: counter(cb,upper-alpha) ". "; }

ol.c { counter-reset: cc; }
ol.b>li { list-style-type: none; font-size: large; }    
ol.ap ol.c>li { font-size: small; }  
ol.ap ol.c>li:before { counter-increment: cc; content: counter(cb,upper-alpha) "." counter(cc) ". "; }

p.main {   font-size: x-large; margin: -0.6em 0; }