Simon game feedback

Hi, friends. http://codepen.io/pbweb/full/qaWLGO/ Here is my simon game. Hope get some feedback.

Really nice job.

One minor issue, the ‘on’ label doesn’t quite fit correctly viewed in my browser, it drops down onto the yellow button:

Thank you for the feedback! Please, tell me what browser.Today I tried to solve it in chrome. I think it’s ok now.