body {
    width: 95%;
    height: 97.5vh;
    background: linear-gradient(to bottom, skyblue, white);
    font-family: Georgia, 'Times New Roman', Times, serif;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    animation: fadein 3.0s forwards;
}

@keyframes fadein {
    0% {opacity: 0;}
    100% {opacity: 1;}
}

.choose {
    border: none;
}

.choose-list {
    list-style: none;
    display: flex;
    justify-content: center;
    padding: 0;
}

.choose-list-item {
    font-size: 25px;
    margin-left: 50px;
    margin-right: 50px;
}

.choose-list-item a {
    color: white;
    text-decoration: none;
    padding: 10px 10px;
    height: 130px;
    width: 130px;
    border-radius: 50%;
    background: linear-gradient(to bottom, white, skyblue);
    display: flex;
    text-align: center;
    justify-content: center;
    flex-direction: column;
    transition: 1.4s;
}

.choose-list-item a:hover {
    transform: scale(1.2, 1.2);
}

.back {
    border: none;
}

.backintroduce {
    list-style: none;
    display: flex;
    justify-content: center;
    padding: 0;
}

.backintroduce-item {
    font-size: 25px;
}

.backintroduce-item  a {
    text-decoration: none;
    color: white;
    width: 130px;
    height: 130px;
    border-radius: 50%;
    background: linear-gradient(to bottom, white, skyblue);
    display: flex;
    text-align: center;
    justify-content: center;
    flex-direction: column;
    padding: 0;
    transition: 1.4s;
}

.backintroduce-item a:hover {
    transform: scale(1.2, 1.2);
}