/* ==========================================================================
   LIGHTBOX — fullscreen viewer
   Owner: UI-3 (public/css/lightbox.css)

   Brief: in the viewer the interface should all but disappear — black,
   weightless, the photograph and nothing else. Motion is slow, confident,
   expensive-feeling. No bounce, no cartoon easing.

   Every color/space/radius/shadow/easing/duration/z-index below is read
   from UI-1's tokens.css via the two-arg var() form, so a naming mismatch
   degrades to a sane literal instead of breaking. The viewer intentionally
   stays dark in BOTH site themes (see CONTRACT.md §5), so the core surface
   colors below lean on raw/invariant-leaning token names rather than the
   semantic --color-bg/--color-text pair, which are expected to flip with
   [data-theme]. If tokens.css later exposes better invariant names, only
   the fallbacks in this alias block need to change.
   ========================================================================== */

#lightbox {
  /* Remapped onto tokens.css's theme-invariant "cinema" family: these back
     surfaces that sit on a photograph and must NOT flip with [data-theme].
     The semantic --color-text/-border/-accent trio would invert in the light
     theme and wreck the viewer (pale hairlines glowing, dark accent on black). */
  --lb-void: var(--color-ink, #0d0b0a);
  --lb-paper: var(--color-scrim-text, #f7f1e6);
  --lb-dim: var(--color-scrim-text-muted, rgba(247, 241, 230, .72));
  --lb-faint: var(--color-scrim-border, rgba(247, 241, 230, .35));
  --lb-hover: rgb(var(--color-scrim-text-rgb, 247 241 230) / .08);
  --lb-accent: var(--color-scrim-accent, #cf9484);

  --lb-radius: var(--radius-md, .5rem);
  --lb-radius-sm: var(--radius-sm, .25rem);
  --lb-radius-full: var(--radius-full, 999px);
  --lb-shadow: var(--shadow-lg, 0 20px 60px rgba(0, 0, 0, .55));

  --lb-ease: var(--ease-out-expo, cubic-bezier(.16, 1, .3, 1));
  --lb-ease-soft: var(--ease-in-out, cubic-bezier(.65, 0, .35, 1));
  --lb-dur-open: var(--dur-cinematic, 900ms);
  --lb-dur-close: var(--dur-base, 350ms);
  --lb-dur-med: var(--dur-slow, 550ms);
  --lb-dur-fast: var(--dur-fast, 180ms);
  --lb-zoom: 1.8;
  --lb-z: var(--z-lightbox, 1000);

  position: fixed;
  inset: 0;
  z-index: var(--lb-z);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background: var(--lb-void);
  color: var(--lb-paper);
  padding: env(safe-area-inset-top) env(safe-area-inset-right)
           env(safe-area-inset-bottom) env(safe-area-inset-left);
  opacity: 0;
  transition: opacity var(--lb-dur-close) var(--lb-ease-soft);
}

#lightbox[hidden] {
  display: none;
}

html.lb-open #lightbox {
  opacity: 1;
  transition: opacity var(--lb-dur-open) var(--lb-ease);
}

/* -------------------------------------------------------------------------
   Backdrop — plain click-to-close hit layer. #lightbox is already the void
   color, so this needs no fill of its own.
   ------------------------------------------------------------------------- */

.lightbox__backdrop {
  position: absolute;
  inset: 0;
  z-index: 0;
  cursor: zoom-out;
}

/* -------------------------------------------------------------------------
   Ambient blur wash — JS points #lbBlur at the current photo (background
   image). Heavily blurred, dimmed and over-scaled so it reads as ambient
   light bleeding from behind the frame rather than a legible picture.
   ------------------------------------------------------------------------- */

.lightbox__blur {
  position: absolute;
  inset: -8%;
  z-index: 1;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  filter: blur(60px) saturate(1.15) brightness(.5);
  transform: scale(1.12);
  opacity: 0;
  transition: opacity var(--lb-dur-close) var(--lb-ease-soft);
  pointer-events: none;
}

html.lb-open .lightbox__blur {
  opacity: .8;
  transition: opacity var(--lb-dur-open) var(--lb-ease);
}

/* -------------------------------------------------------------------------
   Stage + image
   ------------------------------------------------------------------------- */

.lightbox__stage {
  position: relative;
  z-index: 2;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.lightbox__img {
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: contain;
  border-radius: var(--lb-radius-sm);
  box-shadow: var(--lb-shadow);
  scale: .94;
  opacity: 0;
  transition: scale var(--lb-dur-close) var(--lb-ease-soft),
              opacity var(--lb-dur-close) var(--lb-ease-soft);
  touch-action: pinch-zoom;
}

html.lb-open .lightbox__img {
  scale: 1;
  opacity: 1;
  transition: scale var(--lb-dur-open) var(--lb-ease),
              opacity var(--lb-dur-open) var(--lb-ease);
}

#lightbox.is-loading .lightbox__img {
  filter: blur(6px);
  opacity: .55;
  transition: filter var(--lb-dur-fast) linear, opacity var(--lb-dur-fast) linear;
}

#lightbox.is-zoomed .lightbox__img {
  scale: var(--lb-zoom);
  cursor: grab;
  transition: scale var(--lb-dur-fast) var(--lb-ease-soft);
}

#lightbox.is-zoomed .lightbox__img:active {
  cursor: grabbing;
}

/* -------------------------------------------------------------------------
   Spinner — thin single-arc loader, only visible while the full-res image
   is still decoding. `translate` handles centering so `transform` stays
   free for the rotate keyframe (the two would otherwise fight — an element
   only ever has one `transform` value at a time).
   ------------------------------------------------------------------------- */

.lightbox__spinner {
  position: absolute;
  top: 50%;
  left: 50%;
  translate: -50% -50%;
  z-index: 3;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: var(--lb-radius-full);
  border: 2px solid transparent;
  border-top-color: var(--lb-paper);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--lb-dur-fast) linear, visibility 0s linear var(--lb-dur-fast);
  pointer-events: none;
}

#lightbox.is-loading .lightbox__spinner {
  opacity: .85;
  visibility: visible;
  transition: opacity var(--lb-dur-fast) linear;
  animation: spin 900ms linear infinite;
}

/* -------------------------------------------------------------------------
   Chrome shell — spans the viewport so bar / nav / filmstrip can dock to
   their edges; only re-enable pointer events on the actual controls so the
   empty middle keeps letting clicks reach the backdrop/stage beneath it.
   ------------------------------------------------------------------------- */

.lightbox__chrome {
  position: absolute;
  inset: 0;
  z-index: 4;
  pointer-events: none;
}

.lightbox__chrome > * {
  pointer-events: auto;
}

/* -------------------------------------------------------------------------
   Top bar — counter, filename, tools
   ------------------------------------------------------------------------- */

.lightbox__bar {
  position: absolute;
  top: 0;
  inset-inline: 0;
  z-index: 3;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.125rem clamp(1rem, 4vw, 2rem);
  background: linear-gradient(to bottom, rgba(0, 0, 0, .5), transparent);
  opacity: 0;
  transform: translateY(-.75rem);
  transition: opacity var(--lb-dur-close) var(--lb-ease-soft),
              transform var(--lb-dur-close) var(--lb-ease-soft);
}

html.lb-open .lightbox__bar {
  opacity: 1;
  transform: none;
  transition: opacity var(--lb-dur-med) var(--lb-ease) .12s,
              transform var(--lb-dur-med) var(--lb-ease) .12s;
}

.lightbox__counter {
  display: flex;
  align-items: baseline;
  gap: .35em;
  margin: 0;
  flex: 0 0 auto;
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
  font-size: .9375rem;
  letter-spacing: .04em;
  color: var(--lb-paper);
  white-space: nowrap;
}

.lightbox__counter i {
  font-style: normal;
  color: var(--lb-dim);
}

.lightbox__name {
  flex: 1 1 auto;
  min-width: 0;
  margin: 0;
  padding-inline: 1rem;
  font-size: .8125rem;
  color: var(--lb-dim);
  text-align: center;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.lightbox__tools {
  display: flex;
  align-items: center;
  gap: .25rem;
  flex: 0 0 auto;
}

/* -------------------------------------------------------------------------
   Ghost buttons — minimal, generous tap targets, real contrast on black.
   ------------------------------------------------------------------------- */

.lb-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.75rem;
  min-height: 2.75rem;
  padding: 0 .875rem;
  border: 1px solid transparent;
  border-radius: var(--lb-radius-full);
  background: transparent;
  color: var(--lb-paper);
  font-size: .8125rem;
  letter-spacing: .02em;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition: background-color var(--lb-dur-fast) var(--lb-ease-soft),
              border-color var(--lb-dur-fast) var(--lb-ease-soft),
              opacity var(--lb-dur-fast) var(--lb-ease-soft);
}

.lb-btn:hover {
  background: var(--lb-hover);
  border-color: var(--lb-faint);
}

.lb-btn:focus-visible {
  outline: 2px solid var(--lb-accent);
  outline-offset: 2px;
}

.lb-btn:active {
  opacity: .75;
}

/* -------------------------------------------------------------------------
   Prev / next — large invisible hit zones, glyph drawn in pure CSS (a
   rotated two-border corner), fades in only on hover/focus. Touch devices
   rely on swipe, so the zones are removed entirely where there's no hover.
   ------------------------------------------------------------------------- */

.lb-nav {
  position: absolute;
  top: 0;
  bottom: 0;
  z-index: 2;
  width: 28%;
  max-width: 16rem;
  display: flex;
  align-items: center;
  border: 0;
  background: transparent;
  cursor: pointer;
  opacity: 0;
  transition: opacity var(--lb-dur-close) var(--lb-ease-soft);
}

html.lb-open .lb-nav {
  opacity: 1;
  transition: opacity var(--lb-dur-med) var(--lb-ease) .12s;
}

.lb-nav--prev {
  left: 0;
  justify-content: flex-start;
  padding-left: clamp(1rem, 3vw, 2.5rem);
}

.lb-nav--next {
  right: 0;
  justify-content: flex-end;
  padding-right: clamp(1rem, 3vw, 2.5rem);
}

.lb-nav::before {
  content: "";
  width: .8rem;
  height: .8rem;
  opacity: 0;
  transition: opacity var(--lb-dur-fast) var(--lb-ease-soft),
              translate var(--lb-dur-fast) var(--lb-ease-soft);
}

.lb-nav--prev::before {
  border-top: 2px solid var(--lb-paper);
  border-left: 2px solid var(--lb-paper);
  transform: rotate(-45deg);
}

.lb-nav--next::before {
  border-top: 2px solid var(--lb-paper);
  border-right: 2px solid var(--lb-paper);
  transform: rotate(45deg);
}

.lb-nav:hover::before,
.lb-nav:focus-visible::before {
  opacity: .9;
}

.lb-nav--prev:hover::before { translate: -.2rem 0; }
.lb-nav--next:hover::before { translate: .2rem 0; }

.lb-nav:focus-visible {
  outline: 2px solid var(--lb-accent);
  outline-offset: -4px;
}

@media (hover: none) {
  .lb-nav {
    display: none;
  }
}

/* -------------------------------------------------------------------------
   Filmstrip
   ------------------------------------------------------------------------- */

.lightbox__filmstrip {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 3;
  display: flex;
  gap: .5rem;
  padding: .75rem clamp(1rem, 4vw, 2rem) 1rem;
  overflow-x: auto;
  overflow-y: hidden;
  scroll-snap-type: x proximity;
  scrollbar-width: none;
  background: linear-gradient(to top, rgba(0, 0, 0, .5), transparent);
  mask-image: linear-gradient(to right, transparent 0, #000 2.5rem, #000 calc(100% - 2.5rem), transparent 100%);
  -webkit-mask-image: linear-gradient(to right, transparent 0, #000 2.5rem, #000 calc(100% - 2.5rem), transparent 100%);
  opacity: 0;
  transform: translateY(.75rem);
  transition: opacity var(--lb-dur-close) var(--lb-ease-soft),
              transform var(--lb-dur-close) var(--lb-ease-soft);
}

.lightbox__filmstrip::-webkit-scrollbar {
  display: none;
}

html.lb-open .lightbox__filmstrip {
  opacity: 1;
  transform: none;
  transition: opacity var(--lb-dur-med) var(--lb-ease) .18s,
              transform var(--lb-dur-med) var(--lb-ease) .18s;
}

.film {
  flex: 0 0 auto;
  width: 2.75rem;
  height: 2.75rem;
  padding: 0;
  border: 0;
  border-radius: var(--lb-radius-sm);
  overflow: hidden;
  cursor: pointer;
  scroll-snap-align: center;
  opacity: .48;
  filter: saturate(.55) brightness(.72);
  translate: 0 0;
  scale: 1;
  box-shadow: 0 0 0 0 transparent;
  transition: opacity var(--lb-dur-fast) var(--lb-ease-soft),
              filter var(--lb-dur-fast) var(--lb-ease-soft),
              translate var(--lb-dur-fast) var(--lb-ease-soft),
              scale var(--lb-dur-fast) var(--lb-ease-soft),
              box-shadow var(--lb-dur-fast) var(--lb-ease-soft);
}

.film img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.film:hover {
  opacity: .8;
  filter: saturate(.85) brightness(.9);
  translate: 0 -.2rem;
}

.film.is-active {
  opacity: 1;
  filter: none;
  scale: 1.08;
  box-shadow: 0 0 0 2px var(--lb-void), 0 0 0 4px var(--lb-accent);
}

.film:focus-visible {
  opacity: 1;
  outline: 2px solid var(--lb-accent);
  outline-offset: 2px;
}

/* -------------------------------------------------------------------------
   Idle-hidden chrome — controls fade after ~2.5s of inactivity. Highest
   specificity in the file on purpose, so it always wins over the open-state
   rules above regardless of source order, and always transitions fast (no
   stagger delay) whichever direction it's toggled from.
   ------------------------------------------------------------------------- */

#lightbox.lb-chrome-hidden .lightbox__bar {
  opacity: 0;
  transform: translateY(-.6rem);
  transition: opacity var(--lb-dur-fast) var(--lb-ease-soft),
              transform var(--lb-dur-fast) var(--lb-ease-soft);
  pointer-events: none;
}

#lightbox.lb-chrome-hidden .lightbox__filmstrip {
  opacity: 0;
  transform: translateY(.6rem);
  transition: opacity var(--lb-dur-fast) var(--lb-ease-soft),
              transform var(--lb-dur-fast) var(--lb-ease-soft);
  pointer-events: none;
}

#lightbox.lb-chrome-hidden .lb-nav {
  opacity: 0;
  transition: opacity var(--lb-dur-fast) var(--lb-ease-soft);
  pointer-events: none;
}

@media (hover: hover) and (pointer: fine) {
  #lightbox.lb-chrome-hidden .lightbox__stage {
    cursor: none;
  }
}

/* Never trap keyboard focus inside idle-hidden chrome. */
#lightbox.lb-chrome-hidden .lightbox__bar:focus-within,
#lightbox.lb-chrome-hidden .lightbox__filmstrip:focus-within {
  opacity: 1;
  transform: none;
  pointer-events: auto;
  transition-duration: var(--lb-dur-fast);
}

#lightbox.lb-chrome-hidden .lb-nav:focus-visible {
  opacity: .9;
  pointer-events: auto;
}

/* ==========================================================================
   Breakpoints — mobile-first. Filmstrip grows from a compact strip into a
   more generous one; everything else already flexes fluidly via clamp().
   ========================================================================== */

@media (min-width: 48rem) {
  .film {
    width: 3.5rem;
    height: 3.5rem;
  }

  .lightbox__filmstrip {
    gap: .625rem;
    padding: 1rem 2rem 1.25rem;
  }

  .lightbox__counter {
    font-size: 1rem;
  }

  .lightbox__name {
    font-size: .875rem;
  }
}

@media (min-width: 64rem) {
  .film {
    width: 4.25rem;
    height: 4.25rem;
  }

  .lightbox__bar {
    padding-block: 1.5rem;
  }

  .lightbox__filmstrip {
    padding-block: 1.25rem 1.5rem;
  }
}

@media (min-width: 90rem) {
  .lightbox__img {
    border-radius: var(--lb-radius);
  }

  .film {
    width: 4.75rem;
    height: 4.75rem;
  }
}