style.css

*{
    margin: 0;
    padding: 0;
}

main{
    background: white;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: 'Poppins', sans-serif;
    cursor:crosshair;
    /* imp css property */
    perspective: 1000px;
}

.container{
    width: 30rem;
    background:white;
    display: flex;
    justify-content: center;
    align-items: center;
}

.card{
    background: white;
    min-height: 80vh;  
    width: 17.5rem;
    margin: 2rem;
    border-radius: 2rem;
    box-shadow: 0 20px 20px rgba(0, 0, 0, 0.2), 0 0px 40px rgba(0, 0, 0, 0.2);

    /* imp css property */
    transform-style: preserve-3d;
}

.sneaker{
    display: flex;  
    justify-content: center;
    align-items: center;
    padding: 3rem 0 2rem 0;
}

.sneaker img{
    width: 60%;
    z-index: 2;
}

.circle{
    height: 8rem;
    width: 8rem;
    background: linear-gradient(
    to right,
    rgba(245, 70, 66, 0.75),
    rgba(8, 83, 156, 0.75)
  ); 
    position: absolute;
    border-radius: 50%;   
    z-index: 1;
}

.title{
    font-size: 1.5rem;
    padding: 1rem 3rem;
}

.desc{
    padding: 0 3rem;
    font-size: 10px;
    font-weight: 400;
}

.sizes{
    padding: 1rem 3rem;
    display: flex;
    justify-content: space-between;
}


.btn{
    border: none;
    padding: .2rem 1rem;
    border-radius: 2rem;
    font-size: 10px;
    background: white;
    box-shadow:  0px 5px 10px rgba(0, 0, 0, 0.2);
    font-weight: bolder;
    color: grey;
    outline: none;
    cursor: pointer;
}

.active{
    background: rgba(128, 128, 128, 0.544);
    color: black;
    box-shadow:  0px 5px 10px rgba(0, 0, 0, 0.55);
}

.purchase{
    padding: 2rem 3rem;
}

.purchase-btn{
    border: none;
    padding: .5rem;
    border-radius: 2rem;
    font-size: 8px;
    background: #f54642;
    box-shadow:  0px 5px 10px rgba(0, 0, 0, 0.2);
    font-weight: bolder;
    width: 100%;
    color: white;
    outline: none;
    cursor: pointer;
}