style.css

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', 'sans-serif';
    /* background: linear-gradient(120deg, #2c3e50, #34495e); */
    /* background: linear-gradient(120deg, #ff6b6b, #3a1c71); */

}

.wrapper{
    width: 100vw;
    height: 100vh;
    /* background: linear-gradient(120deg, #ff6b6b, #3a1c71); */
    background-image: linear-gradient(120deg, #141414, #000000);
    display: grid;
    place-items:center;
}

.game-info{
    color: white;
    position: absolute;
    top: 3rem;
    left: 50%;
    transform: translateX(-50%);
    background-color: rgba(255, 255, 255, 0.15);
    border-radius: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.15);
    padding: 0.5rem 3rem;
    text-align: center;
}
/* boxes */
.tic-toc-toe{
    width: 90%;
    max-width: 20rem;
    background-color: rgba(255, 255, 255, 0.15);
    border-radius: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.15);
    padding: 2rem;
    display: grid;
    grid-template-columns: repeat(3 , 1fr);
    aspect-ratio: 1/1;
}
/*individual box */
.box{
    position: relative;
    width: 100%;
    aspect-ratio: 1/1;
    cursor: pointer;
    font-size: 3rem;
    color: white;
    display: flex;
    justify-content: center;
    align-items: center;
}
/* border for boxes */
.box1 , .box2  , .box4  , .box5{
    border-right: 2px solid white;
    border-bottom: 2px solid white;
}
.box3 , .box6{
    border-bottom: 2px solid white;
}
.box7 , .box8{
    border-right: 2px solid white;
}

/* new game button */
.btn{
    color: white;
    position: absolute;
    bottom: 3rem;
    left: 50%;
    transform: translateX(-50%);
    background-color: rgba(255, 255, 255, 0.15);
    border-radius: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.15);
    padding: 0.5rem 2rem;
    cursor: pointer;
    display: none;
}
.btn.active{
    display: flex;
}
/* winner diplay */
.win{
   background-color : rgba(0, 255, 0 , 0.3) ;
}