body {
    background-color: #121212;
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.calculadora {
    background-color: #1e1e1e;
    padding: 20px;
    border-radius: 15px; 
    box-shadow: 0px 10px 25px rgba(0, 0, 0, 0.5); 
}

#visor {
    width: 100%;
    height: 50px;
    background-color: #2a2a2a;
    border: none;
    border-radius: 8px;
    color: #fff;
    font-size: 24px;
    text-align: right;
    padding: 10px;
    box-sizing: border-box;
    margin-bottom: 15px;
}

.botoes-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr); 
    gap: 10px;
}

button {
    height: 50px;
    font-size: 20px;
    border: none;
    border-radius: 8px;
    background-color: #333;
    color: #fff;
    cursor: pointer;
    transition: background-color 0.2s;
}

button:hover {
    background-color: #444;
}