/* thumbs.css — page-thumbnail strip shown during a tile drag (Task F8).
   thumbs.js mounts .thumb-strip on <body>, fixed and centered just above
   the pager (the exact `bottom` is set inline from the measured .pager
   top so the strip always clears the dots/arrows row).

   Hit-testing is coordinate-based (document.elementsFromPoint in
   thumbs.js): the drag clone is pointer-events:none AND sits below the
   strip in z-order, so it can neither block hit-testing nor cover the
   targets. The strip itself is hit-testable from the instant it mounts
   (.live, toggled synchronously in show()); .show only animates the
   opacity fade — on hide() both classes go, so the fading card can
   neither swallow a click nor answer a hit-test. */

.thumb-strip {
  position: fixed;
  left: 50%;
  bottom: 64px; /* fallback; thumbs.js writes the measured value inline */
  z-index: 110; /* above the drag clone (100): the clone may pass under
                   the strip but never covers or shadows the targets */
  transform: translateX(-50%);
  display: flex;
  gap: 8px;
  max-width: calc(100vw - 24px); /* internal scroll, never body overflow */
  padding: 8px;
  overflow-x: auto;
  overflow-y: hidden;
  overscroll-behavior: contain;
  scrollbar-width: thin;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--card);
  box-shadow: var(--shadow);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.18s ease;
}

/* Mounted + hit-testable the moment a drag begins — pointer capture on
   the viewport means the strip can't steal the gesture anyway. Kept
   separate from .show so the opacity fade never gates hit-testing. */
.thumb-strip.live {
  pointer-events: auto;
}

.thumb-strip.show {
  opacity: 1;
}

/* ---------- one thumbnail = one page ---------- */

.thumb {
  flex: 0 0 auto;
  /* Mini cell metrics, shrunk by the narrow-viewport media query. */
  --tc: 10px;
  --tg: 2px;
  /* Hit-area floor: every page target is at least ~64×48 px on desktop
     (~48×40 under the 640px media query) no matter how small the
     configured grid makes the mini preview. */
  min-width: 64px;
  min-height: 48px;
  display: flex; /* center the mini grid inside the padded hit area */
  align-items: center;
  justify-content: center;
  padding: 5px;
  border-radius: 8px;
  border: 1.5px solid var(--border);
  background: color-mix(in srgb, var(--fg) 5%, transparent);
}

.thumb-grid {
  display: grid;
  /* --t-rows/--t-cols are set inline per thumb by thumbs.js. */
  grid-template-columns: repeat(var(--t-cols, 6), var(--tc));
  grid-template-rows: repeat(var(--t-rows, 4), var(--tc));
  gap: var(--tg);
}

.thumb-cell {
  width: var(--tc);
  height: var(--tc);
  border-radius: 2px;
  /* Empty slot: a faint square; icon cells get an inline background. */
  background: color-mix(in srgb, var(--fg) 13%, transparent);
  background-size: cover;
  background-position: center;
  display: flex;
  align-items: center;
  justify-content: center;
}

.thumb-cell--icon {
  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--fg) 12%, transparent);
}

/* No fetched icon: a colored dot (color set inline, avatar palette). */
.thumb-dot {
  display: block;
  width: 60%;
  height: 60%;
  border-radius: 50%;
}

/* The dragged bookmark's live slot, echoing .tile.tile-source. */
.thumb-cell--src {
  outline: 1.5px dashed var(--accent);
  outline-offset: -1px;
}

/* Current page (accent border) and the page under the pointer. */
.thumb--current {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}

.thumb--hover {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 18%, transparent);
}

/* Narrow screens: smaller thumbnails; the strip scrolls horizontally
   when the pages don't fit. */
@media (max-width: 640px) {
  .thumb-strip {
    gap: 6px;
    padding: 6px;
    max-width: calc(100vw - 16px);
  }

  .thumb {
    --tc: 7px;
    --tg: 1.5px;
    min-width: 48px;
    min-height: 40px;
    padding: 4px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .thumb-strip {
    transition: none; /* thumbs.js removes it on a timer, not transitionend */
  }
}