html{
    background-image: url(https://upload.wikimedia.org/wikipedia/commons/thumb/9/96/Kol%C3%ADn_n%C3%A1dra%C5%BE%C3%AD_budova_2.jpg/1024px-Kol%C3%ADn_n%C3%A1dra%C5%BE%C3%AD_budova_2.jpg);
    background-repeat: no-repeat;   
    background-size: cover;
}
body{ 
    margin: 0;
    font-family: 'Lucida Sans', 'Lucida Sans Regular', 'Lucida Grande', 'Lucida Sans Unicode', Geneva, Verdana, sans-serif;
    font-weight: bolder;
    
    background: rgba(255, 255, 255, 0.644);
}