I followed the lesson: SilverStripe Lessons » Introduction to frontend forms » Silverstripe CMS
But I got very ugly UI 
Please see the image:
I don’t know why but form-control class is added both to div element + input element. I tried to remove form-control class from div element then it looks good (First input Name)
But I don’t know why it happens.
Can someone help me to explain ? Thank you so much!