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

body {
    height: 100vh;
    width: 100vw;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    background-color: #000;
    width: 50%;
    border-radius: 20px;
    padding: 50px 20px 20px 20px;
    margin: 0 auto;
    max-width: 300px;
}

.container input {
    width: 100%;
    margin-bottom: 10px;
    padding: 10px;
    font-size: 1.5rem;
    background-color: transparent;
    outline: none;
    border: none;
    color: #717171;
    font-size: 1rem;
    text-align: right;
}

.display-formula {
    color: #fff;
    float: right;
    font-size: 2rem;
    font-weight: 700;
}

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

.buttons > :last-child {
    background-color: rgb(255, 123, 0);
}

.container button {
    padding: 30%;
    border-radius: 100%;
    border: none;
    background-color: rgb(44, 44, 44);
    color: #fff;
    font-size: 1.1rem;
}