style.css

@import url('https://fonts.googleapis.com/css2?family=Smooch+Sans&display=swap');

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

.fundo{
    background-color: #192A32;
    height: 100vh;
    font-family: 'Smooch Sans', sans-serif;
    text-align: center;
}

.calculadora{
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    padding: 15px;
    background-color: #2e4652;
    border-radius: 5px;
    box-shadow: 0px 1px 5px black;
}

.marca{
    font-size: 42px;
    color: #31C3BF;
    font-weight: bold;
}

#resultado{
    width: 222px;
    background-color: white;
    box-shadow: 0px 1px 5px black;
    height: 40px;
    text-align: right;
    margin: 5px;
    padding: 5px;
    font-size: 22px;
    border-radius: 10px;
}

.botao{
    cursor: pointer;
    width: 50px;
    height: 50px;
    font-size: 20px;
    margin: 3px;
    background-color: #2e4652;
    color: #31C3BF;
    box-shadow: 0px 1px 5px black;
    font-weight: bold;
    border-radius: 5px;
    border: none;
}

.color{
    color: #F2B138;
}