body{
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            margin: 0;
            background-color: #f4f4f4; /* Light neutral background */
            font-family: Arial, sans-serif;
        }
 
        .calculator {
            background-color: #ffffff; /* White background */
            border-radius: 12px;
            padding: 20px;
            box-shadow: 0px 4px 6px rgba(0, 0, 0, 0.1);
            width: 300px;
        }
 
        .display {
            background-color: #f9f9f9; /* Light gray display */
            color: #333333; /* Dark gray text */
            border-radius: 8px;
            padding: 10px;
            text-align: right;
            font-size: 1.5rem;
            box-shadow: inset 0 0 3px rgba(0, 0, 0, 0.1);
            margin-bottom: 15px;
            height: 80px;
            overflow: hidden;
            display: flex;
            flex-direction: column;
            justify-content: space-between;
        }
 
        .previous-calculation {
            font-size: 1.2rem;
            color: #888888; /* Lighter gray for previous calculation */
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
        }
 
        .current-calculation {
            font-size: 2rem;
        }
 
        .buttons {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 10px;
        }
 
        button {
            background-color: #e0e0e0; /* Light gray buttons */
            color: #333333; /* Dark gray text */
            border: none;
            border-radius: 8px;
            padding: 15px;
            font-size: 1.2rem;
            cursor: pointer;
            transition: background-color 0.2s;
        }
 
        button:hover {
            background-color: #d6d6d6; /* Slightly darker gray on hover */
        }
 
        .operator {
            background-color: #cfd8dc; /* Subtle blue-gray for operators */
        }
 
        .operator:hover {
            background-color: #b0bec5; /* Darker blue-gray on hover */
        }
 
        .span-two {
            grid-column: span 2;
        }