Resultant CSS has duplicate attributes #77

This was reported by SonarCloud to us when I copied the CSS file from a Github release to our project. Sure enough, they are there in the SASS when I look there as well.

1. Unexpected duplicate "position" for .nt-timeline-dot
2. Unexpected duplicate "transition" for .period
3. Unexpected duplicate "border" for .week, .day
4. Unexpected duplicate "padding" for .span-table td, .span-table th

My CSS/SASS fu is weak so I don't have confidence that there wasn't reasoning behind these. I also would have tried to contribute a fix but, again, weak fu.

The rule it is being caught up with in SonarCloud "Properties should not be duplicated":

CSS allows duplicate property names but only the last instance of a duplicated name determines the actual value that will be used for it. Therefore, changing values of other occurrences of a duplicated name will have no effect and may cause misunderstandings and bugs.