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

body,
html {
    width: 100%;
    height: 100vh;
}

:root {
    --Gray: #a5a5a5;
    --White: #f9f9f9;
    --Orange: #FF9F0A;
    --Black: #000000;
    --Light-gray: #343434;
}

.container {
    width: 100%;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--Gray);
}

.calculator {
    background-color: var(--Black);
    padding: 20px;
    border-radius: 15px;
}

.calculator form input {
    border: none;
    outline: none;
    width: 60px;
    height: 60px;
    background: transparent;
    border-radius: 50px;
    font-size: 1.40rem;
    font-weight: 500;
    cursor: pointer;
    margin: 10px;
}

form .display {
    display: flex;
    justify-content: flex-end;
    margin: 20px 0;
}

form .display input {
    flex: 1;
    text-align: right;
    font-size: 1.70rem;
    color: var(--White);
}

form input::placeholder {
    color: var(--White);
}

form input.equal {
    background-color: var(--Orange);
    width: 145px;
}

form input.gray-color {
    background-color: var(--Gray);
}

form input.orange-color {
    background-color: var(--Orange);
}

form input.light-color {
    background-color: var(--Light-gray);
    color: var(--White);
}

@media screen and (max-width:479px) {
    .container {
        background-color: var(--Black);
        padding: 4px;
    }
    ::-webkit-scrollbar {
        display: none;
    }
}