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

.calculadora{
    background-color: #c5c4c4;
    padding: 20px;
    max-width: 400px;
    margin: 0 auto;
    border: solid 1px #ccc;
    box-shadow: 0 2px 5px rgba(0,0,0, 0.3);
    border-radius: 5px;
    margin-top: 40px;
}

#resultado{
    width: 100%;
    padding: 10px;
    font-size: 24px;
    border: none;
    box-shadow: 0 2px 5px rgba(0,0,0, 0.3) 
    inset;
    border-radius: 5px;
}

.buttons{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-gap: 10px;
    margin-top: 20px;
}

button{
    padding: 10px;
    font-size: 24px;
    border: none;
    box-shadow: 0 2px 5px rgba(0,0,0, 0.3);
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3 ease;
}

button:hover{
    background-color: #ddd;

}

.limpar{
    background-color: red;
    color: #fff;

}

.numero{
    background-color: #fff;
    font-family: Verdana, Geneva, Tahoma, sans-serif, Times, serif
}

.numero, .decimal{
    background-color: #fff;
    color: #333;
}

.operadores{
    background-color: #ff6f00;
    color: #fff;
}

.igual{
    background-color: rgb(195, 255, 0);
    grid-row: span 3;
    color: #fff;
}