Yesterday I fought in Arena 4 PEKKA's Playhouse and moved to arena 5 and arena 5 cards were unlocked. So I waited for those card to appear in shop. And to my surprise, today only Mirror appeared in shop. I want that card, but I am short 300 gold, I can use gems in place of them but if I play for the crown chest I might move back to arena 4. So, even if I move down arena, card shop for today will not change right? Mirror will still be there or not?
The cards in the store will not update during the day, so if you lose rank you will still have access to those cards until the next rollover time.
But, if you have a lower rank during rollover, cards accessible at the higher rank will not show up in the shop despite the fact that you had access to them before.