.logo-mask{
  width:80px; height:80px; 
  background:#0EA5E9;                           /* barva loga */
  -webkit-mask: url('https://www.ubpro.eu/B/uploads/--kk--/og-image.jpg') no-repeat center / contain;
          mask: url('https://www.ubpro.eu/B/uploads/--kk--/og-image.jpg') no-repeat center / contain;
}

.logo-mask{ color:#0EA5E9; }
@media (prefers-color-scheme: dark){
  .logo-mask{ color:#0EA5E9; }      /* světlejší v dark módu */
}
@media (max-width: 768px) {
logo{font-size:10px;}
}