body,
html{
    height: 100vh;
    width: 100%;
}

body{
    background: #43cea2;  /* fallback for old browsers */
    background: -webkit-linear-gradient(to right, #185a9d, #43cea2);  /* Chrome 10-25, Safari 5.1-6 */
    background: linear-gradient(to right, #185a9d, #43cea2); /* W3C, IE 10+/ Edge, Firefox 16+, Chrome 26+, Opera 12+, Safari 7+ */
    position: relative;
}

#card {
    margin: 0 auto;
    padding: 0;
    box-sizing: border-box;
    background-color: #fff;
    width: 350px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.item:nth-of-type(2n) {
    background-color: #f8f9fa;
    border-color: #f8f9fa;
}