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

.container {
    width: 100%;
    height: 100vh;
    display: grid;
    place-items: center;
}

main {
    width: 500px;
    padding: 10px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
}

main button {
    font-size: 30px;
    padding: 15px;
    margin: 3px;
    cursor: pointer;
}

.output {
    width: 100%;
    font-style: 30px;
    background: #fff;
    box-shadow: 0 0 7px 1px rgba(0,0,0,0.3);
    height: 50px;
    margin-bottom: 5px;
    display: flex;
    align-items: center;
    font-size: 30px;
    padding: 0 10px;
}