.postcard { width: 100vw; height: 100vh; background-attachment: fixed; background-size: cover; background-position: 50% 50%; z-index: -1; filter: blur(7px) contrast(50%) brightness(50%); position: fixed; top: 0; left: 0; user-select: none; pointer-events: none; } @media (prefers-color-scheme: light) { .postcard { filter: blur(7px) contrast(25%) brightness(175%); } } .postcard-visible { z-index: 1; filter: none; }