Before opening an issue:-[Search for duplicate or closed issues](https://github.com/twbs/bootstrap/issues?utf8=%E2%9C%93&q=is%3Aissue)-[Validate](http://validator.w3.org/nu/) and [lint](https://github.com/twbs/bootlint#in-the-browser) any HTML to avoid common problems- Prepare a [reduced test case](https://css-tricks.com/reduced-test-cases/) for any bugs- Read the [contributing guidelines](https://github.com/twbs/bootstrap/blob/master/CONTRIBUTING.md)When asking general "how to" questions:- Please do not open an issue here- Instead, ask for help on [StackOverflow, IRC, or Slack](https://github.com/twbs/bootstrap/blob/master/README.md#community)When reporting a bug, include:- Operating system and version (Windows, Mac OS X, Android, iOS, Win10 Mobile)- Browser and version (Chrome, Firefox, Safari, IE, MS Edge, Opera 15+, Android Browser)- Reduced test cases and potential fixes using [JS Bin](https://jsbin.com)When suggesting a feature, include:- As much detail as possible for what we should add and why it's important to Bootstrap- Relevant links to prior art, screenshots, or live demos whenever possible