<span class="timer" id="s2" style='font-size:16px; color: #A6ABB9;'></span>
<script>
function countdown( elementName, minutes, seconds )
{
    var element, endTime, hours, mins, msLeft, time;
    function twoDigits( n )
    {
        return (n <= 9 ? "0" + n : n);
    }
    function updateTimer()
    {
        msLeft = endTime - (+new Date);
        if ( msLeft < 1000 ) {
            // soundData should contain any valid file converted to base64
            // look up "file to base64" to get one
            // if you want the particular addon alert, check here https://github.com/glutanimate/speed-focus-mode/blob/main/src/speed_focus_mode/sounds/alert.mp3
            const soundData = "";
            const snd = new Audio(`data:audio/mp3;base64,${soundData}`);
            sound.play();
            element.innerHTML = "<span style='color:#CC5B5B'>TIME</span>";
        } else {
            time = new Date( msLeft );
            hours = time.getUTCHours();
            mins = time.getUTCMinutes();
            element.innerHTML = (hours ? hours + ':' + twoDigits( mins ) : mins) + ':' + twoDigits( time.getUTCSeconds() );
            setTimeout( updateTimer, time.getUTCMilliseconds() + 500 );
        }
    }
    element = document.getElementById( elementName );
    endTime = (+new Date) + 1000 * (60*minutes + seconds) + 500;
    updateTimer();
}
countdown("s2", 0, 10 ); //2nd value is the minute, 3rd is the seconds
</script>