.perspective-1000 {
    perspective: 1000px;
}

.memory-card {
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.5s;
    cursor: pointer;
}

.memory-card.flipped {
    transform: rotateY(180deg);
}

.memory-card.matched .front-face {
    background-color: #d1fae5; /* emerald-100 */
    border-color: #10b981;
    color: #059669;
}
.dark .memory-card.matched .front-face {
    background-color: #064e3b;
    border-color: #059669;
    color: #34d399;
}

.front-face, .back-face {
    width: 100%;
    height: 100%;
    position: absolute;
    backface-visibility: hidden;
    border-radius: 1rem;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
}

.front-face {
    transform: rotateY(180deg);
    font-size: 2.5rem;
}

.back-face {
    background: linear-gradient(135deg, #6366f1, #a855f7);
    color: white;
    font-size: 2rem;
}