/* Site-wide soft background (light theme). Drawn on a fixed pseudo-element
   rather than background-attachment:fixed, which iOS Safari ignores. Dark
   theme keeps its plain dark background — a pale image would clash with it. */
body::before{
  content:"";
  position:fixed; inset:0; z-index:-1;
  background:#F5F6F8 url("/bg-light.jpg") center / cover no-repeat;
  pointer-events:none;
}
[data-theme="dark"] body::before{display:none;}