body{font-family:'Arial',sans-serif;margin:0;padding:20px;background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);min-height:100vh;color:#333;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;-webkit-touch-callout:none;-webkit-tap-highlight-color:transparent}.container{max-width:700px;margin:0 auto;background:rgba(255,255,255,0.95);border-radius:15px;padding:20px;box-shadow:0 10px 30px rgba(0,0,0,0.3)}h1{text-align:center;color:#2c3e50;margin-bottom:20px;font-size:2.5em;text-shadow:2px 2px 4px rgba(0,0,0,0.1)}.info-panel{background:#f8f9fa;border:2px solid #e9ecef;border-radius:8px;padding:15px;margin-bottom:20px}.info-panel p{margin:5px 0;font-size:14px}.board-selector{display:flex;justify-content:center;gap:10px;margin-bottom:20px;flex-wrap:wrap}.board-btn{background:linear-gradient(45deg,#95a5a6,#7f8c8d);color:white;border:0;padding:10px 20px;border-radius:5px;cursor:pointer;font-size:14px;transition:all .3s ease;box-shadow:0 4px 8px rgba(0,0,0,0.2)}.board-btn:hover{transform:translateY(-2px);box-shadow:0 6px 12px rgba(0,0,0,0.3)}.board-btn.active{background:linear-gradient(45deg,#3498db,#2980b9);box-shadow:0 0 15px rgba(52,152,219,0.6)}.controls{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px;flex-wrap:wrap;gap:10px}button:not(.board-btn){background:linear-gradient(45deg,#3498db,#2980b9);color:white;border:0;padding:10px 20px;border-radius:5px;cursor:pointer;font-size:14px;transition:all .3s ease;box-shadow:0 4px 8px rgba(0,0,0,0.2)}button:not(.board-btn):hover{transform:translateY(-2px);box-shadow:0 6px 12px rgba(0,0,0,0.3)}button:active{transform:translateY(0)}#tileCounter{background:#34495e;color:white;padding:8px 15px;border-radius:20px;font-weight:bold;font-size:14px}#gameBoard{display:grid;grid-template-columns:repeat(8,50px);grid-template-rows:repeat(8,50px);gap:0;justify-content:center;background:#34495e;padding:10px;border-radius:10px;margin:20px auto;box-shadow:0 4px 8px rgba(0,0,0,0.3);width:fit-content;position:relative}.square{width:50px;height:50px;cursor:pointer;transition:all .2s ease;border:1px solid rgba(0,0,0,0.1);position:relative}.square.white{background:#f0d9b5}.square.black{background:#b58863}.square.blocked{background:linear-gradient(135deg,#e74c3c,#c0392b);cursor:not-allowed}.square.blocked::after{content:'✕';position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);color:white;font-size:24px;font-weight:bold}.square:not(.blocked):not(.covered):hover{opacity:.8;transform:scale(1.05)}.square.selected{box-shadow:0 0 0 3px #f39c12 inset;opacity:.9}.square.covered{cursor:pointer}.domino{position:absolute;background:rgba(52,152,219,0.8);border:0;border-radius:0;cursor:pointer;transition:all .2s ease;pointer-events:all;box-shadow:0 0 0 2px rgba(52,152,219,1)}.domino:hover{background:rgba(231,76,60,0.9);box-shadow:0 0 0 2px rgba(231,76,60,1)}.instructions{background:#f8f9fa;border-radius:8px;padding:20px;margin-top:20px;border-left:4px solid #3498db}.instructions h3{margin-top:0;color:#2c3e50}.instructions ul{padding-left:20px}.instructions li{margin:8px 0;line-height:1.4}@media(max-width:768px){body{padding:10px}.container{margin:5px;padding:10px;max-width:100%}h1{font-size:1.8em;margin-bottom:15px}.info-panel{padding:10px;margin-bottom:15px;font-size:13px}.board-selector{gap:5px}.board-btn{padding:8px 12px;font-size:12px}.controls{justify-content:center;text-align:center;gap:8px;margin-bottom:15px}button:not(.board-btn){padding:8px 12px;font-size:12px}#tileCounter{padding:6px 10px;font-size:12px}#gameBoard{grid-template-columns:repeat(8,35px);grid-template-rows:repeat(8,35px);padding:8px;margin:10px auto}.square{width:35px;height:35px}.square.blocked::after{font-size:18px}.instructions{padding:15px;font-size:13px}.instructions li{margin:6px 0}}@media(max-width:480px){.container{margin:2px;padding:8px}h1{font-size:1.5em;margin-bottom:10px}.info-panel{padding:8px;margin-bottom:10px;font-size:12px}.controls{flex-direction:column;gap:5px;margin-bottom:10px}button:not(.board-btn){width:100%;max-width:200px;padding:10px;font-size:12px}#gameBoard{grid-template-columns:repeat(8,30px);grid-template-rows:repeat(8,30px);padding:6px}.square{width:30px;height:30px}.square.blocked::after{font-size:16px}.instructions{padding:10px;font-size:12px}}