.box {
    max-width: 400px;
    border: 6px solid #303030;
    padding: 6px;
}

h2 {
    text-transform: uppercase;
}

label {
    text-transform: uppercase;
    vertical-align: sub;
    display: block;
    font-size: 0.7em;
}

input[type="range"] {
    width: 20ch;
}

input:invalid {
    background-color: #ff5f5f;
}