body {
    display: flex;
    justify-content: center;
    align-items: center;  
    min-height: 100vh;  
    
    margin: 0;
    background-color: #f0f0f0;
    font-family: Arial, sans-serif;
}

.calculator {
    width: 320px;
    background-color: #3a4452;
    border-radius: 15px;
    padding: 20px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

#display {
    width: 100%;
    height: 70px;
    margin-bottom: 20px;
    padding: 0 20px;
    font-size: 2.5em;
    text-align: right;
    border: none;
    border-radius: 10px;
    background-color: #1c2128;
    color: white;
    box-sizing: border-box; 
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

button {
    height: 65px;
    font-size: 1.5em;
    font-weight: bold;
    border-radius: 10px;
    border: none;
    cursor: pointer;
    background-color: #2e3641;
    color: #e0e0e0;
    transition: background-color 0.2s;
}

button:hover {
    background-color: #4b5563;
}

.operator {
    background-color: #ff9500;
    color: white;
}

.operator:hover {
    background-color: #ffad33;
}

#clear {
    background-color: #f64242;
    color: white;
    grid-column: span 2;
}

#clear:hover {
    background-color: #f86b6b;
}

#equals {
    grid-row: span 2;
}

.span-two {
    grid-column: span 2;
}