WEBVTT

NOTE
opacity: 0.5; should apply.
color: green; should apply.
background: green; should apply because multiple STYLE blocks are supported.

STYLE
::cue {
    opacity: 0.5;
}
::cue {
    color: green;
}

STYLE
::cue {
    background: green;
}

00:00:00.000 --> 00:00:05.000
<v Voice1>This <i>is</i> a <b>test</b> subtitle

00:00:00.000 --> 00:00:05.000
<v Voice2>Here <i>is</i> a <b>second</b> subtitle