h1.chapter { page-break-before:avoid; margin-top:150px; }
h2.chapter2 { page-break-before:avoid; margin-top:150px; }
h3.chapter3 { page-break-before:avoid; margin-top:100px; }
h4.chapter4 { page-break-before:avoid; margin-top:100px; }
h5.chapter5 { page-break-before:avoid; margin-top:150px; }
h6.chapter6 { page-break-before:avoid; margin-top:150px; }