h1 {
    text-align: center;
}

h2 {
    position: relative;
    text-align: center;
    color: rgba(0, 0, 0, .5);
    top: -20px;
}

button {
    height: 50px;
    width: 150px;
    font-size: 16px;
    text-align: center;
    margin-left: 16px;
    margin-right: 16px;
    margin-top: 16px;
}

button.add {
    color: green;
}

button.sub {
    color: red
}

.buttons {
    display: flex;
    align-items: center;
    justify-content: center;
}

a {
    text-align: center;
    align-items: center;
    display: flex;
    justify-content: center;
    margin-top: 20px;
}