body{
    margin:0;
    height:100vh;
    display:flex;
    justify-content:center;
    align-items:center;
    background:#1e1e2f;
    font-family:Arial;
    color:white;
}

.game-container{
    text-align:center;
}

.grid{
    display:grid;
    grid-template-columns:repeat(4,100px);
    gap:15px;
    justify-content:center;
    margin:20px auto;
}

.card{
    width:100px;
    height:100px;
    perspective:1000px;
    cursor:pointer;
}

.card-inner{
    width:100%;
    height:100%;
    position:relative;
    transform-style:preserve-3d;
    transition:transform 0.5s;
}

.card.flip .card-inner{
    transform:rotateY(180deg);
}

.card-front,
.card-back{
    position:absolute;
    width:100%;
    height:100%;
    border-radius:10px;
    display:flex;
    justify-content:center;
    align-items:center;
    font-size:40px;
    backface-visibility:hidden;
}

.card-front{
    background:#2f2f45;
}

.card-back{
    background:#4CAF50;
    transform:rotateY(180deg);
}

button{
    margin-top:20px;
    padding:10px 20px;
    border:none;
    border-radius:6px;
    background:#ff6b6b;
    color:white;
    cursor:pointer;
}