window.addEventListener('load', function() {
    var preload = document.querySelector('.preload'),
        playBtn = document.querySelector('.preload-button'),
        player = document.querySelector('.player'),
        aliceIn = document.querySelector('.alice1'),
        aliceOut = document.querySelector('.alice3'),
        moan = document.querySelector('.moan');
    moan.addEventListener('playing', function() {
        aliceIn.classList.add('heartbeat-in');
        aliceOut.classList.add('heartbeat-out');
    });
    preload.addEventListener('click', function() {
        preload.classList.add('hidden');
        player.classList.remove('hidden');
        moan.play();
    });
    playBtn.classList.remove('hidden');
});