CSS changes ignored in Tiga 1.06 theme

What could cause the CSS styles to be ignored?

I am running the Tiga 1.06 theme (with some additions) at http://optimalportfolio.net/TaxPolicy/. Thought I could just modify the .post-metadata to switch from padding-left:3em to text-align:center, but neither change has any impact on content presentation in any browser.

I also tried to reduce the .post-author margin-bottom from 3em to 1em – that also had no impact on rendering.

Tried clearing browser cache, opening a browser that had never been open on the site before (so there couldn’t possibly be any cached style page). How are these style elements controlled???

Thanks, Mike
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