.transform-style-preserve-3d{transform-style:preserve-3d}.backface-hidden{backface-visibility:hidden}.rotate-y-180{transform:rotateY(180deg)}.rotate-y-0{transform:rotateY(0deg)}.flashcard-container{transition:transform .7s ease-in-out}.flashcard-hover:hover{transform:translateY(-2px);box-shadow:0 8px 25px rgba(0,0,0,.1)}@keyframes flip{0%{transform:rotateY(0deg)}50%{transform:rotateY(90deg)}to{transform:rotateY(180deg)}}.flip-animation{animation:flip .7s ease-in-out}.difficulty-star{transition:all .2s ease-in-out}.difficulty-star:hover{transform:scale(1.2)}.progress-bar{transition:width .3s ease-in-out}.flashcard-button{transition:all .2s ease-in-out}.flashcard-button:hover{transform:translateY(-1px)}.stats-counter{transition:all .3s ease-in-out}.category-badge{transition:all .2s ease-in-out}.category-badge:hover{transform:scale(1.05)}