/*
 * motion.css - shared motion / UX foundation (load FIRST so page CSS can override).
 *
 * Contract
 *   Tokens        --dur-xs/s/m/l/xl, --ease-out/in/in-out/spring, --stagger, --focus-ring
 *   Attributes    [data-enter]  rise-in entrance; delay = var(--i,0) * var(--stagger)
 *                 [data-exit]   sink-out exit (TopUI.exitAndRemove)
 *                 [hidden]      always display:none
 *   Images        img.top-img (+ .is-loaded / .is-error) fade in after decode
 *   Placeholders  .top-skeleton (shimmer block)
 *                 .top-state (+ .top-state-title, .top-state-msg, .top-state-retry)
 *   Overlays      .top-overlay[data-state=open|closing|closed] > .top-overlay-panel
 *                 <dialog class="top-dialog"> with ::backdrop fade
 *   Scroll lock   html.top-scroll-lock (uses --top-scrollbar-w set by TopUI)
 *   Page change   cross-document @view-transition (progressive enhancement)
 */

:root {
  --dur-xs: 120ms;
  --dur-s: 180ms;
  --dur-m: 260ms;
  --dur-l: 420ms;
  --dur-xl: 700ms;
  --ease-out: cubic-bezier(.22, 1, .36, 1);
  --ease-in: cubic-bezier(.4, 0, 1, 1);
  --ease-in-out: cubic-bezier(.65, 0, .35, 1);
  --ease-spring: cubic-bezier(.34, 1.56, .64, 1);
  --stagger: 40ms;
  --focus-ring: #d8b4ff;
}

/* Existing display:grid/flex rules would otherwise defeat the hidden attribute. */
[hidden] { display: none !important; }

:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 3px;
}

html.top-scroll-lock {
  overflow: hidden;
  padding-right: var(--top-scrollbar-w, 0px);
}

/* ---------- Icons (sprite: image/icons.svg) ---------- */
.icon {
  display: inline-block;
  flex: none;
  width: 1em;
  height: 1em;
  color: inherit;
  vertical-align: -0.125em;
  pointer-events: none;
}

/* ---------- Keyframes ---------- */
@keyframes top-fade-in  { from { opacity: 0; } to { opacity: 1; } }
@keyframes top-fade-out { from { opacity: 1; } to { opacity: 0; } }
@keyframes top-rise-in  { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
@keyframes top-sink-out { from { opacity: 1; transform: none; } to { opacity: 0; transform: translateY(10px); } }
@keyframes top-scale-in  { from { opacity: 0; transform: scale(.96); } to { opacity: 1; transform: none; } }
@keyframes top-scale-out { from { opacity: 1; transform: none; } to { opacity: 0; transform: scale(.96); } }
@keyframes top-shimmer { from { background-position: 200% 0; } to { background-position: -200% 0; } }

/* ---------- Enter / exit ---------- */
[data-enter] {
  animation: top-rise-in var(--dur-m) var(--ease-out) both;
  animation-delay: calc(var(--i, 0) * var(--stagger));
}
[data-exit] {
  animation: top-sink-out var(--dur-s) var(--ease-in) both;
  pointer-events: none;
}

/* ---------- Images ---------- */
img.top-img {
  opacity: 0;
  transition: opacity var(--dur-l) var(--ease-out);
}
img.top-img.is-loaded,
img.top-img.is-error { opacity: 1; }

/* ---------- Skeleton ---------- */
.top-skeleton {
  display: block;
  min-height: 120px;
  border-radius: 12px;
  background: linear-gradient(100deg,
    rgba(185, 132, 255, .06) 30%,
    rgba(216, 180, 255, .16) 50%,
    rgba(185, 132, 255, .06) 70%);
  background-size: 200% 100%;
  animation: top-shimmer 1.6s linear infinite;
}

/* ---------- Loading / error / empty state ---------- */
.top-state {
  grid-column: 1 / -1;
  width: 100%;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 48px 20px;
  text-align: center;
  color: rgba(216, 180, 255, .72);
  animation: top-fade-in var(--dur-m) var(--ease-out) both;
}
.top-state-title { margin: 0; font-size: 1.05rem; color: rgba(236, 220, 255, .9); }
.top-state-msg { margin: 0; font-size: .9rem; }
.top-state-retry {
  appearance: none;
  font: inherit;
  cursor: pointer;
  padding: 8px 22px;
  border-radius: 999px;
  border: 1px solid rgba(185, 132, 255, .5);
  background: rgba(185, 132, 255, .14);
  color: #eadcff;
  transition: transform var(--dur-s) var(--ease-out), background-color var(--dur-s) var(--ease-out);
}
@media (hover: hover) {
  .top-state-retry:hover { transform: scale(1.03); background: rgba(185, 132, 255, .26); }
}
.top-state-retry:active { transform: scale(.97); }

/* ---------- Overlay / dialog ---------- */
.top-overlay[data-state="open"] { animation: top-fade-in var(--dur-m) var(--ease-out) both; }
.top-overlay[data-state="closing"] { animation: top-fade-out var(--dur-s) var(--ease-in) both; pointer-events: none; }
.top-overlay[data-state="open"] .top-overlay-panel { animation: top-scale-in var(--dur-m) var(--ease-out) both; }
.top-overlay[data-state="closing"] .top-overlay-panel { animation: top-scale-out var(--dur-s) var(--ease-in) both; }

dialog.top-dialog[open] { animation: top-scale-in var(--dur-m) var(--ease-out) both; }
dialog.top-dialog[open]::backdrop { animation: top-fade-in var(--dur-m) var(--ease-out) both; }
dialog.top-dialog[data-state="closing"] { animation: top-scale-out var(--dur-s) var(--ease-in) both; }
dialog.top-dialog[data-state="closing"]::backdrop { animation: top-fade-out var(--dur-s) var(--ease-in) both; }
dialog.top-dialog::backdrop { background: rgba(10, 5, 20, .7); }

/* ---------- Cross-document page transitions ---------- */
@view-transition { navigation: auto; }
::view-transition-old(root) { animation: top-fade-out var(--dur-s) var(--ease-in) both; }
@keyframes top-vt-rise { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
::view-transition-new(root) { animation: top-vt-rise var(--dur-m) var(--ease-out) both; }

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-delay: 0s !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
    transition-delay: 0s !important;
    scroll-behavior: auto !important;
  }
  [data-enter] { opacity: 1; transform: none; }
  .top-skeleton { animation: none; }
  @view-transition { navigation: none; }
  ::view-transition-group(*),
  ::view-transition-old(*),
  ::view-transition-new(*) { animation: none !important; }
}