/* Pair Flip — memory match */
.pair-shell {
  width: min(100% - 2rem, 720px);
  margin: 0 auto;
}

.pair-shell .lede {
  margin-bottom: 1.25rem;
}

.pair-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.85rem;
}

.pair-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem 1.15rem;
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--ink-soft);
}

.pair-stats strong {
  color: var(--ink);
}

.difficulty {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: center;
}

.difficulty span {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--ink-soft);
  margin-right: 0.15rem;
}

.difficulty button {
  appearance: none;
  border: 1px solid var(--line);
  background: var(--tile);
  color: var(--ink-soft);
  font: inherit;
  font-size: 0.85rem;
  font-weight: 700;
  border-radius: 999px;
  padding: 0.35rem 0.75rem;
  cursor: pointer;
}

.difficulty button[aria-pressed="true"] {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.board {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.65rem;
  margin: 0.25rem 0 0.85rem;
  user-select: none;
}

.card {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 1 / 1;
  min-height: 4.5rem;
  margin: 0;
  padding: 0;
  border: none;
  background: transparent;
  appearance: none;
  -webkit-appearance: none;
  cursor: pointer;
  font: inherit;
  color: inherit;
}

.card:disabled {
  cursor: default;
}

.card-inner {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  border-radius: 12px;
}

.card-face {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--line);
  box-sizing: border-box;
  transition: opacity 180ms ease, transform 180ms ease;
}

.card-back {
  background:
    linear-gradient(145deg, rgba(15, 122, 106, 0.18), rgba(240, 162, 2, 0.16)),
    #ffffff;
  color: var(--accent-deep);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.25rem, 4vw, 1.75rem);
  letter-spacing: -0.03em;
  opacity: 1;
  transform: scale(1);
  z-index: 2;
}

.card-front {
  background: #ffffff;
  color: var(--ink);
  opacity: 0;
  transform: scale(0.92);
  z-index: 1;
  pointer-events: none;
}

.card.is-flipped .card-back,
.card.is-matched .card-back {
  opacity: 0;
  transform: scale(0.92);
  pointer-events: none;
}

.card.is-flipped .card-front,
.card.is-matched .card-front {
  opacity: 1;
  transform: scale(1);
  z-index: 3;
}

.card.is-matched .card-front {
  border-color: var(--accent);
  background: rgba(15, 122, 106, 0.1);
}

.card-icon {
  width: 52%;
  height: 52%;
  max-width: 64px;
  max-height: 64px;
}

.card:focus-visible .card-inner {
  outline: 3px solid rgba(15, 122, 106, 0.35);
  outline-offset: 2px;
}

.pair-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.pair-feedback {
  min-height: 1.5rem;
  margin: 0.75rem 0 0;
  font-weight: 700;
}

.pair-feedback.ok {
  color: var(--accent-deep);
}

.play-board.is-celebrate {
  animation: pair-board-glow 750ms ease;
}

@keyframes pair-board-glow {
  0% {
    box-shadow: none;
  }
  45% {
    box-shadow:
      0 0 0 4px rgba(240, 162, 2, 0.45),
      0 14px 34px rgba(15, 122, 106, 0.22);
  }
  100% {
    box-shadow: none;
  }
}

.how-to {
  margin-top: 1rem;
}

.how-to h2 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  letter-spacing: -0.03em;
  margin: 0 0 0.5rem;
}

.how-to p,
.how-to li {
  color: var(--ink-soft);
  margin: 0 0 0.45rem;
}

.how-to ul {
  margin: 0;
  padding-left: 1.15rem;
}

@media (max-width: 480px) {
  .board {
    gap: 0.45rem;
  }
}