:root{--bg-overlay-dark:0.6;--bg-overlay-light:0.5}body.bg-img{background:url(/background.webp)50%/cover no-repeat}body::before{content:"";position:fixed;inset:0;background:rgba(0,0,0,var(--bg-overlay-dark));pointer-events:none;z-index:-1}body.light::before{background:rgba(255,255,255,var(--bg-overlay-light))}