CMS tables - my css for [td]

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Hi there,

I've got a few fairly involved tables I've put together that go way beyond what the normal table settings can handle. Pretty straight forward but one of the tables is 15 columns by 35 rows. 12 of the columns are very small in size, only indicating which months of the year the first three columns values are applicable to by using a different background color for a cell. What hoping to use css for the td class to do this.

[td="class:x1"].[/td]
or
[td="class:x2"].[/td]

Question is, can I attach a style sheet somewhere that'll allow my td class to function as desired within a CMS articles table or will it be more involved than that?