<label for="meeting-time">Choose a time for your appointment:</label>

<input type="datetime-local" id="meeting-time"
       name="meeting-time" value="2018-06-12T19:30"
       min="2018-06-07T00:00" max="2018-06-14T00:00">

label {
    display: block;
    font: 1rem 'Fira Sans', sans-serif;
}

input,
label {
    margin: 0.4rem 0;
}