/* glass-field: the canvas the shader draws on, filling its parent (give the parent position:relative). Until the first
   frame, or without WebGL, a black-to-grey gradient stands in. Needs ../base/base.css. */
.glass-field{position:absolute;inset:0;z-index:-1;width:100%;height:100%;display:block;background:radial-gradient(90% 70% at 50% 30%,#2a2a2a 0%,#0c0c0c 45%,#000 100%)}
/* a section cut to night over its own glass (adrcenter.com's "Copy. Paste. Done."): the canvas goes first inside it */
.sul-vetro{position:relative;isolation:isolate;overflow:hidden}
.sul-vetro>.glass-field{opacity:.9}
/* behind a whole page, still while the page scrolls (the demo page): the body lets it show through */
.glass-field.fisso{position:fixed;inset:0;z-index:-1;height:100vh;height:100lvh}
body:has(>.glass-field.fisso){background:transparent}