* {
    margin: 0;
    padding: 0;
    font-family: 'poppins', sans-serif;
    box-sizing: border-box;
}

.container {
    width: 100%;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background-image: url(https://st.depositphotos.com/1025323/2214/i/950/depositphotos_22142055-stock-photo-realms-of-mathematics.jpg?forcejpeg=true);
    /* background: linear-gradient(to top left, #1eff00, #ff0000) */
}

.calculator {
    background: #0e0c0cf3;
    padding: 10px;
    border-radius: 10px;
}

.calculator form input {
    border: 2;
    outline: 2;
    width: 65px;
    height: 65px;
    border-radius: 10px;
    /* box-shadow: -8px -8px 15px rgba(211, 22, 22, 0.1), 5px, 5px, 15px rgba(0, 0, 0, 0.2); */
    background: transparent;
    font-size: 25px;
    color: #fff;
    cursor: pointer;
    margin: 15px;
}

form .display {
    display: flex;
    justify-content: flex-end;
}

form .display input {
    text-align: right;
    flex: 1;
    font-size: 45px;
    box-shadow: none;
}

input:hover {
    transform: scale(1.04);
    box-shadow: 1px 1px 1px 1px rgb(255, 255, 255);
    transition: 0.2s ease-in-out;
}

form input.operator {
    color: #000000;
    font-size: 1.2em;
    padding: 5px 10px;
    border-radius: 5px;
    border: 1px solid #333;
    box-shadow: 1px 1px 1px rgba(0,0,0,0.1);
    transition: all 0.2s ease-in-out;
    width: 100%;
}

form input.operator:focus {
    outline: none;
    box-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
    border-radius: 4px;
    background-color: #f5f5f5;
}