*{
    font-family: 'Lucida Sans', 'Lucida Sans Regular', 'Lucida Grande', 'Lucida Sans Unicode', Geneva, Verdana, sans-serif;
    box-sizing: border-box;
}
body{
    width: 100%;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background-image: url(calculator.jpg);
    background-size: cover;
}
button{
    width: 55px;
    height: 55px; 
    border-radius: 8px;
    background-color: black;
    color: white;  
}
.calculator{
    border: 2px solid black;
    padding: 20px;
    border-radius: 15px;
    background-color: black;
}
input{
    width: 220px;
    height: 60px;
    border: none;
    padding: 22px;
    margin: 10px;
    font-size: 40px;
    cursor: pointer;
    color: black;
}
input::placeholder{
    color: black;
}