CSS: remove rules for headings
CSS: remove rules for headings

No reason to define font-size values for headings: 1/ It should be
relative to the global font-size, 2/ browser usually have sane values
for those and 3/ let users override them in their local CSS if
necessary.

Signed-off-by: Joel Porquet <4816dabf8db1bc6cac35b3a24cab2ff844b5b0c7@porquet.org>

tripu/remark,FabioBeneditto/remark,FabioBeneditto/remark,tripu/remark,gnab/remark,gnab/remark