.concentration-board{grid-template-columns:repeat(5,minmax(0,1fr));gap:8px;max-width:640px;display:grid}.concentration-board[data-cards="30"]{grid-template-columns:repeat(5,minmax(0,1fr))}@media (width>=640px){.concentration-board[data-cards="30"]{grid-template-columns:repeat(6,minmax(0,1fr));max-width:720px}}.memory-card{aspect-ratio:3/4;perspective:600px;cursor:pointer;background:0 0;border:0;padding:0}.memory-card:disabled{cursor:default}.memory-card:focus-visible{outline:2px solid var(--color-accent);outline-offset:2px;border-radius:10px}.memory-card-inner{width:100%;height:100%;transform-style:preserve-3d;transition:transform .3s;display:block;position:relative}.memory-card.is-flipped .memory-card-inner,.memory-card.is-matched .memory-card-inner{transform:rotateY(180deg)}.memory-card-face{border:1px solid var(--color-border);backface-visibility:hidden;border-radius:10px;justify-content:center;align-items:center;display:flex;position:absolute;inset:0}.memory-card-back{background:repeating-linear-gradient(45deg, transparent 0 8px, #e8b64c14 8px 16px), var(--color-surface-2);color:var(--color-accent);letter-spacing:.05em;font-size:.75rem;font-weight:700}.memory-card-front{background:var(--color-surface);padding:8%;transform:rotateY(180deg)}.memory-card-front img{object-fit:contain;max-width:100%;max-height:100%}.memory-card.is-matched .memory-card-front{border-color:var(--color-accent);box-shadow:0 0 10px #e8b64c59}@media (prefers-reduced-motion:reduce){.memory-card-inner{transition:none}}.memory-card.is-loading .memory-card-front{background:radial-gradient(circle, #e8b64c2e 0 30%, transparent 31%), var(--color-surface)}