#board-container{display:flex;justify-content:center;align-items:center;min-height:100vh;padding-top:4.5rem;background:linear-gradient(180deg,#87ceeb,#5d9e5f,#3d6b3a);position:relative}#board-container:before{content:"";position:absolute;inset:0;background:radial-gradient(circle at 20% 80%,rgba(139,119,73,.3) 0%,transparent 50%),radial-gradient(circle at 80% 20%,rgba(76,175,80,.2) 0%,transparent 40%);pointer-events:none}#board{display:inline-grid;gap:10px;padding:20px;background:#0000004d;border-radius:16px;border:3px solid rgba(139,119,73,.5);box-shadow:0 8px 32px #0006,inset 0 1px #ffffff1a}.card{width:90px;height:100px;perspective:600px;cursor:pointer}.card-inner{width:100%;height:100%;position:relative;transition:transform .5s;transform-style:preserve-3d}.card.flipped .card-inner,.card.matched .card-inner{transform:rotateY(180deg)}.card-front,.card-back{position:absolute;width:100%;height:100%;backface-visibility:hidden;border-radius:10px;display:flex;flex-direction:column;align-items:center;justify-content:center}.card-front{background:linear-gradient(145deg,#7ba05b,#5d8a45,#4a6b38);border:3px solid rgba(0,0,0,.3);box-shadow:inset 0 2px #fff3,inset 0 -2px #0003,0 4px 8px #0000004d}.card-front:after{content:"?";font-family:var(--font-pixel);font-size:2rem;color:#0000004d;text-shadow:1px 1px 0 rgba(255,255,255,.1)}.card:hover .card-front{transform:scale(1.05);box-shadow:inset 0 2px #fff3,0 6px 16px #0006}.card-back{background:linear-gradient(145deg,#5d4037,#4e342e,#3e2723);border:3px solid rgba(139,119,73,.6);transform:rotateY(180deg);box-shadow:0 4px 12px #0006,inset 0 1px #ffffff1a}.card-back .c-icon{font-size:2.4rem;margin-bottom:4px;filter:drop-shadow(2px 2px 2px rgba(0,0,0,.5))}.card-back .c-label{font-family:var(--font-pixel);font-size:.35rem;color:#ffd700e6;text-align:center;text-shadow:1px 1px 0 rgba(0,0,0,.5)}.card.matched .card-back{border-color:gold;box-shadow:0 0 20px #ffd70080,inset 0 0 15px #ffd70033}.card.matched .card-inner{animation:match-pop .4s ease-out}@keyframes match-pop{0%{transform:rotateY(180deg) scale(1)}50%{transform:rotateY(180deg) scale(1.15)}to{transform:rotateY(180deg) scale(1)}}.difficulty-select{display:flex;gap:.8rem;margin-top:1.5rem;flex-wrap:wrap;justify-content:center}.diff-btn{font-size:.5rem!important;padding:.8rem 1.2rem!important;background:linear-gradient(145deg,#5d4037,#4e342e)!important;border:2px solid rgba(139,119,73,.5)!important}.diff-btn:hover{border-color:gold!important;box-shadow:0 0 15px #ffd7004d!important}