@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.cell {
    transition: all 0.3s ease;
}

.cell:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}
.winning-cell {
    animation: pulse 0.5s infinite;
    background-color: rgba(30, 41, 59, 0.2);
}
#game-board {
    perspective: 1000px;
}

.cell-content {
    transform-style: preserve-3d;
    transition: transform 0.5s;
}

.cell-content.x::before, .cell-content.o::before {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    backface-visibility: hidden;
}
.cell-content.x::before {
    content: "X";
    color: #1e293b;
    font-size: 4rem;
}

.cell-content.o::before {
    content: "O";
    color: #64748b;
    font-size: 4rem;
}