.UK-BG {
    background-color: rgba(0, 10, 0, 0.5); 
    top:0; left:0; right:0; bottom:0; 
    width:100vw; height:100vh; 
    position: fixed; 
    display: flex; flex-direction: column; justify-content: center; align-items: center;
    z-index: 1500;
}
.UK-BG .UK-BOX {
    min-width: 30vw;  max-width:95vw; 
    min-height: 10vh; max-height: 95vh; 
    overflow: auto; 
    background-color: transparent;
    border-radius: 0.5rem;
}
.UK-BG .UK-BOX-FIX {
    position: fixed;
    top: 1rem; left: 1rem;
    width:auto; height:auto;
}
/* UK-BOX 的 scrollbar, 很细 */
.UK-BG .UK-BOX::-webkit-scrollbar {
    width: 0.25rem;
}
.UK-BG .UK-BOX::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.1);
}
.UK-BG .UK-BOX::-webkit-scrollbar-thumb {
    background: rgba(0, 0, 0, 0.2);
}