JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html lang="ru">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <title>Таймер</title>
    <link
      rel="stylesheet"
      href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css"
      integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh"
      crossorigin="anonymous"
    />
  </head>
  <body>
    <div class="container">
      <div class="row">
        <div class="time col">
          <span class="minutes">03</span>:<span class="seconds">00</span>
        </div>
      </div>
      <div class="row">
        <div class="button col">
          <button type="button" class="btn button__start">cтарт</button>
          <button type="button" class="btn button__stop">пауза</button>
          <button type="button" class="btn button__reset">сброс</button>
        </div>
      </div>
    </div>
    <script src="script.js"></script>
  </body>
</html>

CSS

.container {
  justify-content: space-between;
}

.time {
  font-size: 100px;
  text-align: center;
}

span {
  width: 130px;
  display: inline-block;
  vertical-align: middle;
}

.button {
  text-align: center;
  margin-top: 30px;
  margin-bottom: 30px;
}

.button__start {
  width: 180px;
  height: 70px;
  margin-right: 30px;
  border-radius: 0;
  background-color: rgb(101, 214, 67);
  color: #fff;
}

.button__stop {
  width: 180px;
  height: 70px;
  margin-right: 30px;
  border-radius: 0;
  background-color: rgb(247, 185, 43);
  color: #fff;
}

.button__reset {
  width: 180px;
  height: 70px;
  border-radius: 0;
  background-color: rgb(235, 38, 31);
  color: #fff;
}

@media (max-width: 576px) {
  .button__start,
  .button__stop {
    margin-right: 0;
  }
}

JavaScript

'use strict';

let start = document.querySelector('.button__start');
let stop = document.querySelector('.button__stop');
let reset = document.querySelector('.button__reset');

let minutes = document.querySelector('.minutes');
let seconds = document.querySelector('.seconds');

let minutesValue = 2;
let secondsValue = 60;

start.addEventListener('click', function() {
  let timer = setInterval(secondsChange, 1000);
  timer;

  function secondsChange() {
    secondsValue--;
    if (secondsValue < 10) {
      secondsValue = '0' + secondsValue;
    }
    if (secondsValue === '0-1') {
      minutesValue--;
      secondsValue = 59;
    }
    if (minutesValue === 0 && secondsValue === '00') {
      clearInterval(timer);
    }
    minutes.innerHTML = '0' + minutesValue;
    seconds.innerHTML = secondsValue;
  }

  stop.addEventListener('click', function() {
    clearInterval(timer);
    start.addEventListener('click', function() {
      timer;
    });
  });

  reset.addEventListener('click', function() {
    minutes.innerHTML = '03';
    seconds.innerHTML = '00';
    minutesValue = 2;
    secondsValue = 60;
  });
});