Why doesn't btn-success bootstrap work when writing code in html. I loaded the bootstrap base, but there is no color for the button?

Question

css

Why doesn't btn-success bootstrap work when writing code in html. The bootstrap base is loaded, but there is no button color?
it should be green, but i don't have the color, what did i do wrong ?
the screen has attached the path of the file, the code and how it will be displayed

The button should be green, but there is no color

Answer 1

.js where?
Read

<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>

Answer 2

You have connected only the grid file, it does not describe the color of the buttons. Include bootstrap.css