* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
html {
    height: 100%;
}

body {
    background: url('/images/gras.jpg') no-repeat center center fixed;
    background-size: cover;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100%;
    font-family: arial, sans-serif;
}

#content {
    border-radius: 15px;
    box-shadow: 0 0 8px rgba(0, 0, 0, 0.4);
    padding: 25px;
    width: 300px;
    background: #FFFFFF;
    text-align: center;
}
#content img {
    display: block;
    margin: 0 auto 20px auto;
}