DONT ADD ANYTHING HERE!

Code

HTML

<video src="../videos/fish.mp4" controls muted>

    <track 
        default 
        kind="captions" 
        src="../tracks/track_example_one.vtt">

</video>

VTT

WEBVTT

NOTE An example of a VTT file

00:00.200 --> 00:01.900 position:10% align:left size:100%
<v Tom><i>Hello World!</i>

00:02.000 --> 00:02.900 position:30%
<v Tom><b>Goodbye</b>

CSS

::cue {
    font-size: 3em;
}

::cue(b) {
    color: red;
}

Notes

Although it does not apply in this case, note that
"If the kind attribute is set to subtitles, then srclang must be defined" (MDN)