html {
    height: 100%;
    font-family: sans-serif;
}

body {
    background:url(img/page-bg-1920x1080.jpg) no-repeat center center fixed;
    background-size: cover;
    height: 100%;
}

main {
    text-align: center;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

a  {
    display: inline-block;
    background: rgb(31, 35, 46);
    border-radius: 20px;
    color: white;
    padding: .5rem 5rem;
    text-decoration: none;
} 

a:hover {
    color: rgb(210, 232, 35);
}