/* Componenti in stile Liquid Glass, realizzati in CSS.
   Struttura di ogni superficie di vetro:
   - riempimento bianco traslucido a gradiente (più luminoso in alto);
   - backdrop-filter: sfoca e satura ciò che sta dietro;
   - ::before: riflesso speculare che segue il dito o il puntatore (--mx, --my, impostati da src/ui/glass.js);
   - ::after: bordo sottile luminoso, più chiaro in alto a sinistra e in basso a destra;
   - ombre interne per lo spessore del vetro, ombra esterna cobalto scuro per la profondità.
   In Chrome, src/ui/glass.js aggiunge la rifrazione sui bordi (elementi con data-lens). */

.glass {
  --mx: 30%;
  --my: 0%;
  --fill-top: var(--glass-fill-top);
  --fill-bottom: var(--glass-fill-bottom);
  --spec: .35;
  position: relative;
  isolation: isolate;
  color: var(--white);
  background: linear-gradient(180deg, var(--fill-top), var(--fill-bottom));
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(170%);
  backdrop-filter: blur(var(--glass-blur)) saturate(170%);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, .45),
    inset 0 -1px 1px rgba(255, 255, 255, .10),
    inset 0 0 12px rgba(255, 255, 255, .06),
    var(--glass-shadow);
  transition:
    transform .5s var(--spring),
    box-shadow .3s var(--ease),
    background .3s var(--ease);
  -webkit-tap-highlight-color: transparent;
}

.glass::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  border-radius: inherit;
  pointer-events: none;
  background:
    radial-gradient(120% 90% at var(--mx) var(--my), rgba(255, 255, 255, var(--spec)), transparent 55%),
    linear-gradient(180deg, rgba(255, 255, 255, calc(var(--spec) * .45)), transparent 45%);
  transition: opacity .3s var(--ease);
}

.glass::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1px;
  pointer-events: none;
  background: linear-gradient(135deg,
    rgba(255, 255, 255, .85) 0%,
    rgba(255, 255, 255, .22) 30%,
    rgba(255, 255, 255, .06) 55%,
    rgba(255, 255, 255, .45) 100%);
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask: linear-gradient(#000 0 0) content-box exclude, linear-gradient(#000 0 0);
}

/* Pressione: il vetro si comprime e si illumina in fretta, poi torna indietro con una molla. */
.glass:is(button, label, a):active,
.glass.is-pressed {
  --fill-top: rgba(255, 255, 255, .30);
  --fill-bottom: rgba(255, 255, 255, .12);
  --spec: .6;
  transform: scale(.95);
  transition-duration: .12s;
  transition-timing-function: var(--ease);
}

@media (hover: hover) {
  .glass:is(button, label, a):hover { --spec: .5; }
}

.glass:focus-visible,
.glass:has(:focus-visible) {
  outline: 2px solid rgba(255, 255, 255, .9);
  outline-offset: 3px;
}

/* ---------- Pulsante a pillola ---------- */

.glass-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: var(--touch);
  padding: 0 24px;
  border: 0;
  border-radius: 999px;
  font: inherit;
  font-size: var(--label-size);
  letter-spacing: var(--label-tracking);
  text-transform: uppercase;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
}

.glass-button--lg {
  min-height: 56px;
  padding: 0 36px;
}

/* Variante principale: vetro quasi opaco, testo cobalto. Una sola per schermata. */
.glass-button--prominent {
  --fill-top: rgba(255, 255, 255, .96);
  --fill-bottom: rgba(255, 255, 255, .80);
  --spec: .9;
  color: var(--cobalt);
}
.glass-button--prominent:active,
.glass-button--prominent.is-pressed {
  --fill-top: rgba(255, 255, 255, 1);
  --fill-bottom: rgba(255, 255, 255, .88);
}

.glass-button[disabled] {
  opacity: .4;
  pointer-events: none;
}

/* ---------- Pulsante rotondo (icone) ---------- */

.glass-round {
  display: inline-grid;
  place-items: center;
  width: var(--touch);
  height: var(--touch);
  padding: 0;
  border: 0;
  border-radius: 50%;
  font: inherit;
  font-size: 20px;
  line-height: 1;
  cursor: pointer;
}
.glass-round--lg {
  width: 64px;
  height: 64px;
}
.glass-round svg {
  width: 40%;
  height: 40%;
  display: block;
}

/* ---------- Selettore a segmenti (A/B, profondità di bit, formato) ---------- */

.segmented {
  --count: 2;
  --index: 0;
  --pad: 4px;
  display: inline-grid;
  grid-auto-flow: column;
  grid-auto-columns: 1fr;
  padding: var(--pad);
  border-radius: 999px;
  min-height: var(--touch);
}
.segmented__thumb {
  position: absolute;
  top: var(--pad);
  bottom: var(--pad);
  left: var(--pad);
  width: calc((100% - 2 * var(--pad)) / var(--count));
  border-radius: 999px;
  transform: translateX(calc(100% * var(--index)));
  transition: transform .55s var(--spring);
  background: linear-gradient(180deg, rgba(255, 255, 255, .42), rgba(255, 255, 255, .18));
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, .7),
    inset 0 0 0 1px rgba(255, 255, 255, .25),
    0 2px 8px rgb(3 22 84 / .3);
  pointer-events: none;
}
.segmented button {
  position: relative;
  z-index: 1;
  min-height: calc(var(--touch) - 2 * var(--pad));
  padding: 0 18px;
  border: 0;
  background: none;
  color: var(--text-3);
  font: inherit;
  font-size: var(--label-size);
  letter-spacing: var(--label-tracking);
  text-transform: uppercase;
  white-space: nowrap;
  cursor: pointer;
  transition: color .25s var(--ease);
  -webkit-tap-highlight-color: transparent;
}
.segmented button[aria-checked="true"] {
  color: var(--white);
}
.segmented button:focus-visible {
  outline: none;
  text-decoration: underline;
  text-underline-offset: 4px;
}

/* ---------- Cursore ----------
   La manopola è bianca piena; mentre la trascini diventa una lente di vetro più grande. */

.glass-range {
  --fill: 50%;
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: var(--touch);
  margin: 0;
  background: transparent;
  cursor: pointer;
  touch-action: pan-y;
}
.glass-range:focus-visible { outline: none; }

.glass-range::-webkit-slider-runnable-track {
  height: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--white) var(--fill), rgba(255, 255, 255, .25) var(--fill));
}
.glass-range::-moz-range-track {
  height: 2px;
  border-radius: 2px;
  background: rgba(255, 255, 255, .25);
}
.glass-range::-moz-range-progress {
  height: 2px;
  background: var(--white);
}

.glass-range::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 28px;
  height: 28px;
  margin-top: -13px;
  border-radius: 50%;
  border: 0;
  background: linear-gradient(180deg, #fff, rgba(255, 255, 255, .88));
  box-shadow: inset 0 -1px 1px rgba(3, 22, 84, .12), 0 4px 12px rgb(3 22 84 / .35);
  transition: transform .45s var(--spring), background .2s, box-shadow .2s;
}
.glass-range::-moz-range-thumb {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 0;
  background: linear-gradient(180deg, #fff, rgba(255, 255, 255, .88));
  box-shadow: inset 0 -1px 1px rgba(3, 22, 84, .12), 0 4px 12px rgb(3 22 84 / .35);
  transition: transform .45s var(--spring), background .2s, box-shadow .2s;
}
.glass-range:active::-webkit-slider-thumb {
  transform: scale(1.35);
  background: linear-gradient(180deg, rgba(255, 255, 255, .5), rgba(255, 255, 255, .18));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .9), inset 0 0 0 1px rgba(255, 255, 255, .5), 0 6px 18px rgb(3 22 84 / .4);
}
.glass-range:active::-moz-range-thumb {
  transform: scale(1.35);
  background: linear-gradient(180deg, rgba(255, 255, 255, .5), rgba(255, 255, 255, .18));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .9), inset 0 0 0 1px rgba(255, 255, 255, .5), 0 6px 18px rgb(3 22 84 / .4);
}
.glass-range:focus-visible::-webkit-slider-thumb { outline: 2px solid #fff; outline-offset: 3px; }
.glass-range:focus-visible::-moz-range-thumb { outline: 2px solid #fff; outline-offset: 3px; }

/* ---------- Accessibilità ---------- */

/* Chi ha chiesto meno trasparenza al sistema ottiene superfici piene, senza sfocatura. */
@media (prefers-reduced-transparency: reduce) {
  .glass {
    -webkit-backdrop-filter: none !important;
    backdrop-filter: none !important;
    background: rgba(255, 255, 255, .18);
  }
  .glass-button--prominent { background: #fff; }
}

@media (prefers-reduced-motion: reduce) {
  .glass,
  .segmented__thumb,
  .glass-range::-webkit-slider-thumb {
    transition-duration: .01s !important;
  }
}