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The default skin is the "classic" skin. The Add a new skin to the global config (CONFIG['APPEARANCE']['skins'] array). As soon as the skin is in the config, the usual way to change it is via fed admin UI; add the new option "Preferred Skin for User Area" and type the string that matches YOURSKIN.
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To make all pages appear in the desired skin, it is possible to hard-code the desired skin in the POST or GET leading to the CAT page. Append a
&skin=YOURSKIN (or POST equivalent)to the link and the UI will show with the desired skin immediately.
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