.grid-board {
  display: grid;
  gap: 0.5rem;
  width: 100%;
  max-width: 400px;
  margin: 0 auto;
}

.light-btn-board {
  --light-cell-edge: #d2dfcf;
  --light-active-edge: #a5aa31;
  position: relative;
  max-width: min(92vw, 420px);
  gap: 0.65rem;
  margin: 0.5rem auto;
}

.grid-cell {
  aspect-ratio: 1;
  min-height: 0;
  width: 100%;
  border: 2px solid var(--light-cell-edge, var(--line));
  border-radius: 10px;
  background: linear-gradient(180deg, #fffefa, #f6f9f0);
  cursor: pointer;
  font-weight: 600;
  color: var(--ink);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color 0.12s, border-color 0.12s, box-shadow 0.12s;
  appearance: none;
  -webkit-appearance: none;
  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
  -webkit-touch-callout: none;
  user-select: none;
  caret-color: transparent;
  outline: none;
  box-shadow: 0 1px 3px rgba(44, 77, 49, 0.055);
}

.light-btn-cell {
  min-height: clamp(3.2rem, 14vw, 5rem);
  font-size: 0;
}

.grid-cell:hover:not(:disabled) {
  border-color: var(--green);
}

html.is-pointer-input .grid-cell:hover:not(:disabled) {
  border-color: var(--light-cell-edge, var(--line));
}
html.is-pointer-input .grid-cell.highlight:hover:not(:disabled) {
  border-color: var(--light-active-edge);
}

.grid-cell.highlight {
  background: #e8df79;
  border-color: var(--light-active-edge);
  box-shadow: 0 1px 5px rgba(114, 117, 40, 0.18);
}

.game-area {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  width: 100%;
  min-height: 140px;
}

.game-area .prompt {
  margin: 0;
  font-size: 1rem;
  font-weight: 800;
  text-align: center;
}

.wrong-flash-overlay {
  display: none !important;
}

.light-btn-board.is-wrong-flash::after {
  content: "";
  position: absolute;
  inset: -8px;
  z-index: 3;
  border-radius: 14px;
  background: rgba(239, 68, 68, 0.34);
  pointer-events: none;
}

.grid-cell:focus,
.grid-cell:focus:not(:focus-visible),
.grid-cell:active {
  outline: none;
  box-shadow: none;
}
html.is-pointer-input .grid-cell:focus,
html.is-pointer-input .grid-cell:focus-visible,
html.is-pointer-input .grid-cell:active {
  outline: none;
  box-shadow: none;
}
html.is-keyboard-nav .grid-cell:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  .grid-cell { transition: none; }
}

@media (max-width: 430px) {
  .light-btn-board {
    gap: 0.4rem;
    max-width: 100%;
    margin: 0.25rem auto;
  }
  .light-btn-cell {
    min-height: clamp(3.6rem, 18vw, 5.4rem);
    border-width: 1px;
    border-radius: 8px;
  }
}

@media (max-height: 760px) and (min-width: 431px) {
  .light-btn-board {
    max-width: min(50vh, 360px);
    gap: 0.4rem;
    margin: 0.2rem auto;
  }
  .light-btn-cell {
    min-height: 0;
  }
  .game-area .prompt {
    font-size: 0.9rem;
  }
}