[assets] add site.css from openmirage.org, differentiated from decks.css
[assets] add site.css from openmirage.org, differentiated from decks.css

samoht/mirage-decks,mirage/mirage-decks,samoht/mirage-decks,yomimono/mirage-decks,magthe/mirage-decks,amirmc/mirage-decks,mor1/mirage-decks,mor1/mirage-decks,yomimono/mirage-decks,magthe/mirage-decks,amirmc/mirage-decks,mirage/mirage-decks