Before opening:

- [Search for duplicate or closed issues](https://github.com/twbs/bootstrap/issues?utf8=%E2%9C%93&q=is%3Aissue)
- [Validate](https://html5.validator.nu/) and [lint](https://github.com/twbs/bootlint#in-the-browser) any HTML to avoid common problems
- Read the [contributing guidelines](https://github.com/twbs/bootstrap/blob/master/.github/CONTRIBUTING.md)

Bug reports must include:

- Operating system and version (Windows, macOS, Android, iOS, Win10 Mobile)
- Browser and version (Chrome, Firefox, Safari, IE, MS Edge, Opera 15+, Android Browser)
- [Reduced test case](https://css-tricks.com/reduced-test-cases/) and suggested fix using [CodePen](https://codepen.io/) or [JS Bin](https://jsbin.com/)
