.links_yj {
            display: flex;
            flex-direction: column;
            align-items: center;
        }
.link_yj {
    margin: 10px 0;
    padding: 10px 20px;
    background-color: #007BFF;
    color: white;
    text-decoration: none;
    border-radius: 5px;
    transition: background-color 0.3s;
}
body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: #f4f4f4;
}