/* apple-upgrade.css — 2026-10-27 — principes du skill apple-design poses PAR-DESSUS le site existant.
   Rien n'est remplace : ce fichier se charge en dernier. Retrait = enlever la ligne <link>. */

/* §1 Reponse — retour a l'appui, sans delai de 300 ms */
a, button, .btn, [role="button"], summary, label[for]{
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.btn, .theme-btn, .hero-cta .btn{
  transition: transform 100ms ease-out, background .18s ease, border-color .18s ease, color .18s ease;
}
.btn:active, button:active, [role="button"]:active{ transform: scale(.97); }
.btn:hover:active{ transform: scale(.97); }

/* §12 Materiaux — barre plus epaisse et BORD DE DEFILEMENT en degrade au lieu d'un filet 1 px */
header.site{
  background: color-mix(in srgb, var(--bg) 62%, transparent);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 0;
  transition: background .3s ease;
}
header.site::after{
  content:""; position:absolute; left:0; right:0; top:100%; height:22px;
  pointer-events:none; opacity:0; transition:opacity .25s ease;
  background: linear-gradient(color-mix(in srgb, var(--ink) 14%, transparent), transparent);
}
body.a-defile header.site{ background: color-mix(in srgb, var(--bg) 82%, transparent); }
body.a-defile header.site::after{ opacity:1; }

/* §12 Vibrancy — sur une surface translucide, le texte gris plat decroche */
header.site .nav .links a{ color: color-mix(in srgb, var(--ink) 72%, transparent); letter-spacing:.004em; }
header.site .nav .links a:hover{ color: var(--ink); }

/* §15 Typographie — tracking et leading selon la taille */
h1{ letter-spacing:-.022em; line-height:1.04; font-optical-sizing:auto; }
h2{ letter-spacing:-.016em; line-height:1.12; }
h3{ letter-spacing:-.010em; line-height:1.20; }
h4, h5{ letter-spacing:-.004em; }
p, li{ line-height:1.6; }
small, figcaption, .fin, .note, .mention, .dchip-t{ letter-spacing:.012em; }
.btn{ letter-spacing:.004em; }

/* §2/§6 Glisse — prise sur les pistes horizontales (moteur dans apple-upgrade.js) */
.ap-piste{ cursor: grab; }
.ap-piste.ap-prise{ cursor: grabbing; user-select:none; }
.ap-piste.ap-prise *{ pointer-events:none; }

/* §14 Accessibilite */
@media (prefers-reduced-motion: reduce){
  *, *::before, *::after{
    animation-duration:.01ms !important; animation-iteration-count:1 !important;
    transition-duration:120ms !important; scroll-behavior:auto !important;
  }
}
@media (prefers-reduced-transparency: reduce){
  header.site{ background: var(--bg); -webkit-backdrop-filter:none; backdrop-filter:none; }
  header.site::after{ display:none; }
}
@media (prefers-contrast: more){
  header.site{ background: var(--bg); border-bottom:1px solid var(--ink); }
  .btn{ border-width:2px; }
}