Revert "Added bottom margin to #topic_header columns css .info col had a different margin setting than the rest. This does not matter as long a you use the default css. But if you change box sizing on all elements ( * { box-sizing:content-box; } ) the .info column of the first row after heading will be pushed to the right."

This reverts commit 8aef869f7c65ca60aae8383dd592969753075fe3.
Added margin bottom to #topic_header columns

Signed-off-by: Michael 'Tekkla' Zorn <tekkla@tekkla.de>