.memory-window { width: min(520px, 94vw); min-height: 560px; }
.memory-board {
    display: grid;
    grid-template-columns: repeat(4, 78px);
    gap: 8px;
}
.memory-card {
    width: 78px;
    height: 78px;
    border: 1px solid #465346;
    background: #171b17;
    color: transparent;
    font-size: 28px;
    cursor: pointer;
}
.memory-card:hover { border-color: #8cff8c; }
.memory-card.revealed,.memory-card.matched {
    color: #b6ff72;
    background: #202620;
}
.memory-card.matched { border-color: #75d675; }
@media (max-width: 560px) {
    .memory-board { grid-template-columns: repeat(4, 62px); gap: 6px; }
    .memory-card { width: 62px; height: 62px; }
}