body {counter-reset: ebene1;}

h1:before {
    content: counter(ebene1) " ";
    counter-increment: ebene1;}
h1 {counter-reset: ebene2;}

h2:before {
    content: counter(ebene1) "." counter(ebene2) " ";
    counter-increment: ebene2;}
h2 {counter-reset: ebene3;}

h3:before {
    content: counter(ebene1) "." counter(ebene2) "." counter(ebene3) " ";
    counter-increment: ebene3;}

.Titel
{
  font-size:2rem;
 line-height: 3;
 font-weight:normal;
}