exporting and that section of the styles area have nothing to do with installing a style
you just upload the style folder to the templates folder right beside the subSilver folder,
then, in your admin panel/styles section, you click on add, then on the right side you should see it listed, you click on install.
now , you go to your profile and choose it. or if you want it to be the default for everyone, you go to the configuration section of the admin panel and choose it and then check the yes button for override users.
I'm baaaaaccckkkk. still doing work on donation basis. PM your needs.
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If nobody is in the forest, does a tree really fall?