* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
    background-color: #74747464;
}

.calculadora {
    width: 300px;
    background-color: #0d1b2a;
    border-radius: 10px;
    box-shadow: 6px 4px 4px #000000;
    font-family: Arial, Helvetica, sans-serif;
    overflow: hidden;
}

.resultado {
    height: 75px;
    padding: 20px;
    text-align: right;
    color: #fff;
    font-size: 2.5rem;
}

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

.botoes button {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    height: 60px;
    color: #fff;
    font-size: 1.5rem;
    font-weight: bold;
    border: none;
    outline: none;
    cursor: pointer;
}

.btZero {
    grid-column: span 2;
}

.btCinza {
    background-color: #1b263b;
}

.btCinzaclaro {
    background-color: #415a77;
}

button:active {
    opacity: 0.9;
}

.btLaranja {
    background-color: #e36414;
}