/* Phase 1 — board interaction */
.board-preview {
  position: relative;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
}

.board-preview__slot {
  display: grid;
  place-items: center;
  min-width: 0;
  transition: border-color 140ms ease, background 140ms ease, box-shadow 140ms ease, transform 160ms cubic-bezier(.2,.8,.2,1);
}

.board-preview__slot--drop-move {
  border-color: rgba(102, 231, 255, 0.86);
  background: radial-gradient(circle at 50% 42%, rgba(102, 231, 255, 0.19), transparent 58%), rgba(12, 36, 48, 0.92);
  box-shadow: inset 0 0 26px rgba(102, 231, 255, 0.12), 0 0 18px rgba(102, 231, 255, 0.11);
}

.board-preview__slot--drop-merge {
  border-color: rgba(255, 201, 103, 0.95);
  background: radial-gradient(circle at 50% 42%, rgba(255, 201, 103, 0.22), transparent 60%), rgba(41, 31, 18, 0.9);
  box-shadow: inset 0 0 30px rgba(255, 201, 103, 0.13), 0 0 24px rgba(255, 201, 103, 0.13);
  transform: scale(1.035);
}

.board-preview__slot--drop-invalid {
  border-color: rgba(255, 101, 133, 0.72);
  box-shadow: inset 0 0 22px rgba(255, 101, 133, 0.08);
}

.board-preview__slot--landed { animation: slot-land 260ms cubic-bezier(.2,.8,.2,1); }
.board-preview__slot--merged { animation: slot-merge 620ms cubic-bezier(.12,.88,.24,1.15); }
.board-preview__slot--merge-source { animation: slot-merge-source 420ms ease-out; }
.board-preview__slot--merge-charge { animation: slot-merge-charge 620ms ease-out; }
.board-preview__slot--rejected .board-unit { animation: unit-reject 350ms ease-out; }

.board-unit {
  position: relative;
  z-index: 2;
  width: 72%;
  aspect-ratio: 1;
  display: grid;
  place-items: center;
  padding: 0;
  border: 1px solid rgba(255, 255, 255, 0.24);
  border-radius: 50%;
  color: white;
  cursor: grab;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  box-shadow: inset 0 -10px 22px rgba(0, 0, 0, 0.25), 0 8px 22px rgba(0, 0, 0, 0.26);
  transition: transform 120ms ease, opacity 120ms ease, box-shadow 120ms ease;
}

.board-unit:active { cursor: grabbing; }
.board-unit--pulse {
  background: radial-gradient(circle at 40% 32%, #b9f8ff 0 9%, #27bad7 30%, #0a6478 70%, #073844 100%);
  box-shadow: inset 0 -10px 22px rgba(0, 0, 0, 0.25), 0 0 20px rgba(102, 231, 255, 0.19);
}
.board-unit--nova {
  background: radial-gradient(circle at 40% 32%, #fff3c1 0 9%, #ffb44f 31%, #9d5217 70%, #522609 100%);
  box-shadow: inset 0 -10px 22px rgba(0, 0, 0, 0.25), 0 0 20px rgba(255, 184, 92, 0.18);
}
.board-unit--cryo {
  background: radial-gradient(circle at 40% 32%, #e9edff 0 9%, #94aaff 31%, #4a5da8 70%, #27315e 100%);
  box-shadow: inset 0 -10px 22px rgba(0, 0, 0, 0.25), 0 0 20px rgba(143, 169, 255, 0.18);
}

.board-unit--dragging { opacity: 0.23; transform: scale(0.88); }
.board-unit--tier-reveal { animation: unit-tier-reveal 640ms cubic-bezier(.14,.88,.2,1.14); }
.board-unit--tier-reveal .board-unit__tier { animation: tier-badge-pop 640ms cubic-bezier(.18,.9,.2,1.18); }
.board-unit--ghost {
  position: fixed;
  left: 0;
  top: 0;
  z-index: 1000;
  width: clamp(58px, 16vw, 84px);
  pointer-events: none;
  opacity: 0.94;
  transform-origin: center;
  box-shadow: inset 0 -10px 22px rgba(0, 0, 0, 0.22), 0 18px 44px rgba(0, 0, 0, 0.38), 0 0 28px rgba(102, 231, 255, 0.17);
}

.board-unit__core {
  font-size: clamp(1rem, 3vw, 1.45rem);
  font-weight: 950;
  line-height: 1;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.38);
}

.board-unit__tier {
  position: absolute;
  right: -6px;
  bottom: -5px;
  min-width: 27px;
  padding: 4px 6px;
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 999px;
  background: rgba(2, 10, 16, 0.92);
  color: #f2fbff;
  font-size: 0.56rem;
  font-weight: 900;
  letter-spacing: 0.04em;
}

.unit-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 9px 14px;
  margin-top: 16px;
  color: #9cb3c0;
  font-size: 0.7rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.unit-legend span { display: inline-flex; align-items: center; gap: 6px; }
.unit-dot { width: 8px; height: 8px; border-radius: 50%; }
.unit-dot--pulse { background: #66e7ff; box-shadow: 0 0 9px rgba(102, 231, 255, 0.72); }
.unit-dot--nova { background: #ffb85c; box-shadow: 0 0 9px rgba(255, 184, 92, 0.62); }
.unit-dot--cryo { background: #8fa9ff; box-shadow: 0 0 9px rgba(143, 169, 255, 0.62); }

.merge-attractor {
  position: fixed;
  z-index: 1100;
  width: 16px;
  height: 16px;
  margin: -8px;
  border: 2px solid rgba(255,255,255,.9);
  border-radius: 50%;
  background: var(--burst-color);
  box-shadow: 0 0 14px var(--burst-color), 0 0 28px var(--burst-color);
  pointer-events: none;
  transform-origin: center;
  animation: merge-attract 480ms cubic-bezier(.3,.05,.18,1) forwards;
}

.merge-attractor::before,
.merge-attractor::after {
  content: "";
  position: absolute;
  inset: 50% auto auto 50%;
  border: 1px solid var(--burst-color);
  border-radius: 50%;
  transform: translate(-50%,-50%);
}
.merge-attractor::before { width: 28px; height: 28px; opacity: .62; }
.merge-attractor::after { width: 40px; height: 40px; opacity: .25; }

.merge-burst {
  position: absolute;
  inset: 50% auto auto 50%;
  z-index: 5;
  width: 0;
  height: 0;
  pointer-events: none;
}
.merge-burst::before,
.merge-burst::after {
  content: "";
  position: absolute;
  transform: translate(-50%, -50%);
  border: 2px solid var(--burst-color);
  border-radius: 50%;
  animation: merge-ring 560ms ease-out forwards;
}
.merge-burst::before { width: 14px; height: 14px; }
.merge-burst::after {
  width: 8px;
  height: 8px;
  opacity: .62;
  animation-delay: 70ms;
}
.merge-burst i {
  position: absolute;
  left: -2px;
  top: -2px;
  width: 4px;
  height: 12px;
  border-radius: 999px;
  background: var(--burst-color);
  box-shadow: 0 0 8px var(--burst-color);
  transform: rotate(var(--particle-angle)) translateY(-12px);
  transform-origin: 2px 2px;
  animation: merge-particle 560ms ease-out forwards;
}

.interaction-message {
  position: fixed;
  left: 50%;
  bottom: max(22px, calc(env(safe-area-inset-bottom) + 10px));
  z-index: 1200;
  max-width: min(88vw, 420px);
  padding: 9px 14px;
  border: 1px solid rgba(102, 231, 255, 0.25);
  border-radius: 999px;
  background: rgba(3, 12, 18, 0.9);
  color: #cceef5;
  font-size: 0.68rem;
  font-weight: 900;
  letter-spacing: 0.1em;
  text-align: center;
  opacity: 0;
  transform: translate(-50%, 10px);
  pointer-events: none;
  transition: opacity 160ms ease, transform 160ms ease;
}
.interaction-message--visible { opacity: 1; transform: translate(-50%, 0); }
.interaction-message[data-tone="merge"] { border-color: rgba(255, 201, 103, 0.48); color: #ffe5ae; }
.interaction-message[data-tone="warning"] { border-color: rgba(255, 101, 133, 0.48); color: #ffd2db; }

@keyframes slot-land { 0% { transform: scale(0.94); } 65% { transform: scale(1.05); } 100% { transform: scale(1); } }
@keyframes slot-merge { 0% { transform: scale(0.92); } 35% { transform: scale(0.88); } 58% { transform: scale(1.13); } 100% { transform: scale(1); } }
@keyframes slot-merge-source { 0% { box-shadow: inset 0 0 0 rgba(255,201,103,0); } 42% { box-shadow: inset 0 0 34px rgba(255,201,103,.32), 0 0 18px rgba(255,201,103,.16); } 100% { box-shadow: inset 0 0 0 rgba(255,201,103,0); } }
@keyframes slot-merge-charge { 0%,100% { border-color: inherit; } 45% { border-color: rgba(255,232,173,.95); box-shadow: inset 0 0 42px rgba(255,201,103,.24), 0 0 28px rgba(255,201,103,.22); } }
@keyframes unit-tier-reveal { 0% { opacity:.72; transform:scale(1); filter:brightness(1); } 22% { opacity:.5; transform:scale(.72); filter:brightness(1.9); } 48% { opacity:1; transform:scale(1.2); filter:brightness(1.65); } 72% { transform:scale(.97); filter:brightness(1.12); } 100% { opacity:1; transform:scale(1); filter:none; } }
@keyframes tier-badge-pop { 0%,30% { opacity:0; transform:scale(.45) rotate(-8deg); } 58% { opacity:1; transform:scale(1.35) rotate(3deg); } 100% { opacity:1; transform:scale(1) rotate(0); } }
@keyframes unit-reject { 0%, 100% { transform: translateX(0); } 24% { transform: translateX(-6px) rotate(-3deg); } 52% { transform: translateX(5px) rotate(2deg); } 76% { transform: translateX(-3px); } }
@keyframes merge-attract { 0% { opacity:1; transform:translate3d(0,0,0) scale(.78); } 72% { opacity:1; transform:translate3d(var(--merge-dx),var(--merge-dy),0) scale(var(--merge-tier-scale,1)); } 86% { opacity:1; transform:translate3d(var(--merge-dx),var(--merge-dy),0) scale(.48); } 100% { opacity:0; transform:translate3d(var(--merge-dx),var(--merge-dy),0) scale(1.8); } }
@keyframes merge-ring { from { opacity: 1; width: 12px; height: 12px; } to { opacity: 0; width: var(--merge-ring-size,100px); height: var(--merge-ring-size,100px); } }
@keyframes merge-particle { from { opacity: 1; transform: rotate(var(--particle-angle)) translateY(-12px) scaleY(1); } to { opacity: 0; transform: rotate(var(--particle-angle)) translateY(var(--merge-particle-distance,-48px)) scaleY(0.45); } }

@media (max-width: 720px) {
  .unit-legend { justify-content: center; margin-top: 10px; font-size: 0.58rem; }
  .board-unit { width: 70%; }
  .board-unit__tier { right: -5px; bottom: -4px; min-width: 24px; padding: 3px 5px; font-size: 0.5rem; }
}

@media (prefers-reduced-motion: reduce) {
  .board-preview__slot, .board-unit, .interaction-message { transition: none; }
  .merge-attractor { display:none; }
  .board-preview__slot--landed,
  .board-preview__slot--merged,
  .board-preview__slot--merge-source,
  .board-preview__slot--merge-charge,
  .board-preview__slot--rejected .board-unit,
  .board-unit--tier-reveal,
  .board-unit--tier-reveal .board-unit__tier,
  .merge-burst::before,
  .merge-burst::after,
  .merge-burst i { animation-duration: 1ms !important; }
}