styles.css

body {
    background-color: white;
    color: black;
    text-align: center;
}

.container{
    width: 100%;
    height: 100vh;
    background: white;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.calculator{
    background: #B0CFDE;
    padding: 25px;
    border: 10px;
    border-color: black;
    box-shadow: 6px 6px 17px rgba(0, 0, 0, 0.8);
}

.calculator form input{
    border: 0;
    outline: 0;
    width: 55px;
    height: 55px;
    border-radius: 60px;
    border-color: black;
    box-shadow: -8px -8px 18px rgba(255, 255, 255, 0.5), 6px 6px 17px rgba(0, 0, 0, 0.7);
    background: transparent;
    font-size: 22px;
    color: black;
    cursor: pointer;
    margin: 12px;
}

form .display{
    display: flex;
    justify-content: flex-end;
    margin: 24px 0;
    border-color: black;
}

form .display input{
    text-align: left;
    flex: 1;
    font-size: 40px;
    box-shadow: none;
    border-color: black;
}

form input.left-bracket{
    width: 140px;
}

form input.right-bracket{
    width: 140px;
}