body{margin:0;padding:0;font-family:Arial,sans-serif;background-color:#f3f3f3;display:flex;justify-content:center;align-items:center;height:100vh}.container{display:grid;grid-template-columns:repeat(4,1fr);grid-template-rows:auto repeat(5,1fr);gap:10px;padding:20px;background-color:#222;border-radius:10px;box-shadow:0 10px 20px #0000004d;width:320px;text-align:center;box-sizing:border-box}.container span{grid-column:span 4;font-size:2rem;color:#fff;margin-bottom:10px}.input{grid-column:span 4;margin-bottom:10px;width:100%;box-sizing:border-box}.input input{width:100%;padding:15px;font-size:1.5rem;text-align:right;border:none;outline:none;background-color:#333;color:#fff;border-radius:5px;box-shadow:inset 0 0 5px #00000080;box-sizing:border-box}button{padding:15px;font-size:1.2rem;border:none;outline:none;border-radius:5px;background-color:#444;color:#fff;cursor:pointer;transition:background-color .3s ease}button:hover{background-color:#555}button[value="="]{background-color:#ff9500;color:#fff}button[value="="]:hover{background-color:#ffad33}button[value=AC],button[value=Back]{background-color:#d9534f;color:#fff}button[value=AC]:hover,button[value=Back]:hover{background-color:#c9302c}@media (max-width: 480px){.container{width:90%;padding:15px;gap:8px}.container span{font-size:1.5rem}.input input{padding:10px;font-size:1.2rem}button{padding:10px;font-size:1rem}}