body{
    background-image: url("Christina_11.jpg");
    width: 100%;
    background-repeat: no-repeat ;
    background-attachment: fixed;
    background-position: center;
    background-size: cover;
    margin: 0;
}
.center {
    margin: 0;
    position: absolute;
    text-align: center;
    color: white;
    font-family: 'Roboto', sans-serif;
    top: 55%;
    left: 50%;
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
}
.button{
    background-color: #ec362f; 
    border: none;
    color: white;
    padding: 15px 32px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 22px;
    border-radius: 5px;
    margin: 4px 2px;
    cursor: pointer;
}
@media (min-width: 320px) and (max-width: 767px) {
    
    body{
        background-image: url("aaa.jpg");
        width: 100%;
        background-repeat: no-repeat ;
        background-attachment: fixed;
        background-position: center;
        background-size: cover;
        overflow-x: hidden;
    }
    .center{
        position: absolute;
        text-align: center;
    }
}
@media (min-width: 768px) and (max-width: 1024px){
    body{
        background-image: url("aaa.jpg");
        width: 100%;
        background-repeat: no-repeat ;
        background-attachment: fixed;
        background-position: center;
        background-size: cover;
        overflow-x: hidden;
    }
    .center{
        position: absolute;
        text-align: center;
    }
}