resolves #1020 remove excess whitespace above content container
resolves #1020 remove excess whitespace above content container

- remove clearing from #content container so margins collapse
- add text-rendering for subheaders

pepijnve/asciidoctor,anthonny/asciidoctor,asciidocfx/asciidoctor,gjtorikian/asciidoctor,gjtorikian/asciidoctor,cuit-zhaxin/asciidoctor,glamouracademy/asciidoctor,neontapir/asciidoctor,cuit-zhaxin/asciidoctor,benignbala/asciidoctor,yukisan/asciidoctor,mjang/mj-asciidoc,neontapir/asciidoctor,asciidocfx/asciidoctor,mjang/mj-asciidoc,glamouracademy/asciidoctor,benignbala/asciidoctor,pepijnve/asciidoctor,yukisan/asciidoctor,anthonny/asciidoctor