The skins in JW Player 7 are pure css. S3Media Stream 7.1 comes with 9 JW Player skins and 3 skins produced by ourselves of which 2 are made specifically for audio (hector_audio & hector_audiovol).
These audio skins were originally made for Hector Belãnos (Mexico) to fit in with his site.
Important: these skins are not compatible with version 8.3 since JW Player changes the skin model dramatically. See Custom skins for version 8.x