/* Bouton de retour à l'accueil : invisible sur le titre d'ouverture, il apparaît ensuite. */
.retour{position:fixed;z-index:40;top:calc(env(safe-area-inset-top,0px) + 14px);left:max(14px,env(safe-area-inset-left,0px));
  display:inline-flex;align-items:center;gap:6px;padding:9px 16px 9px 12px;border-radius:999px;
  font:600 14px/1 -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter","Helvetica Neue",Arial,sans-serif;letter-spacing:.02em;text-decoration:none;
  color:var(--ink,#1d1d1f);background:color-mix(in srgb,var(--bg,#fff) 72%,transparent);
  -webkit-backdrop-filter:saturate(180%) blur(20px);backdrop-filter:saturate(180%) blur(20px);
  border:1px solid color-mix(in srgb,var(--ink,#1d1d1f) 10%,transparent);box-shadow:0 6px 24px rgba(0,0,0,.12);
  opacity:0;transform:translateY(-12px) scale(.96);pointer-events:none;visibility:hidden;
  transition:opacity .45s cubic-bezier(.2,.8,.2,1),transform .45s cubic-bezier(.2,.8,.2,1),visibility 0s linear .45s}
.retour.vu{opacity:1;transform:none;pointer-events:auto;visibility:visible;transition:opacity .45s cubic-bezier(.2,.8,.2,1),transform .45s cubic-bezier(.2,.8,.2,1),visibility 0s}
.retour svg{width:9px;height:15px;flex:0 0 auto}
.retour b{font-weight:800;letter-spacing:.12em;font-size:12.5px}
.retour:hover{background:color-mix(in srgb,var(--bg,#fff) 88%,transparent)}
.retour:focus-visible{outline:2px solid var(--accent,#0071e3);outline-offset:3px}
@media (prefers-reduced-motion:reduce){.retour,.retour.vu{transition:none;transform:none}}