/* Projector page flip (Josiah's idea, Oct 18; preview Nov 14): each main section arrives like an old slide advance:
   a brief dark gap, a warm lamp flicker and a one-pixel frame shake. Once per section, subtle, never on the first screen. */
.pf{position:relative}
.pf.pf-wait{opacity:0}
.pf.pf-go{animation:pfAdvance .62s cubic-bezier(.2,.7,.2,1) both}
.pf.pf-go::after{content:"";position:absolute;inset:-4% -2%;pointer-events:none;z-index:3;
  background:radial-gradient(60% 45% at 50% 38%,rgba(232,201,143,.16),rgba(200,169,106,.05) 55%,transparent 75%);
  mix-blend-mode:screen;animation:pfLamp .62s ease-out both}
@keyframes pfAdvance{
  0%{opacity:0;filter:brightness(.35);transform:translate3d(0,6px,0)}
  16%{opacity:.85;filter:brightness(1.18);transform:translate3d(0,1.5px,0)}
  26%{opacity:.7;filter:brightness(.92);transform:translate3d(-1px,-1px,0)}
  38%{opacity:1;filter:brightness(1.06);transform:translate3d(1px,0,0)}
  52%{filter:brightness(1);transform:translate3d(0,0,0)}
  100%{opacity:1;filter:none;transform:none}}
@keyframes pfLamp{0%{opacity:0}14%{opacity:1}30%{opacity:.35}44%{opacity:.7}100%{opacity:0}}
@media (prefers-reduced-motion:reduce){.pf.pf-wait{opacity:1}.pf.pf-go,.pf.pf-go::after{animation:none}}
@media print{.pf.pf-wait{opacity:1}}