style.css

*{
    box-sizing: border-box;
}

body{
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.box{
    background: white;
    padding: 40px 60px;
    border-radius: 16px;
    position: relative;
    background-image: linear-gradient(to right, #52B6FE, #6154FE);
    width: 295px;
    height: 174px;
}

.box h3{
    color: whitesmoke;
    position: absolute;
    top: 5px;
    padding: 1px;
    left: 20px;
    font-weight: normal;
    font-size: 1rem;
    text-decoration: none;
}

.btn.visa{
    font-size: 2rem;
    color: white;
    position: absolute;
    left: 15rem;
    top: 1rem;
    cursor: default;
}

.box .ccname{
    color: white;
    opacity: 0.7;
    position: absolute;
    left: 1.4rem;
    top: 5rem;
    font-size: 14px;

}

.box .ccnum{
    color: white;
    position: absolute;
    left: 1.4rem;
    bottom: 1rem;
}