How can I stop Discourse from altering my Forum's design?

My forum can be viewed here.

The first issue had to do with the width of my wrapper:

A week or so after I had my look finalized, I visited the forum and noticed that the wrapper was considerably skinnier. Texts that use to take 2 lines to display were now taking 3 or 4.

The second issue is the one I’m reporting in this thread. Where my text broke out of alignment randomly.

I’m just worried because my 28 day trial isn’t even over yet and I’ve already ran into this twice.