How to change btn color in Bootstrap

The easiest way to see which properties you need to override is to take a look at Bootstrap's source code, specifically the .button-variant mixin defined in mixins/buttons.less. You still need to override quite a lot of properties to get rid of all of the .btn-primary styling (e.g. :focus, disabled, usage in dropdowns etc).

A better way might be to:

1. Create your own customized version of Bootstrap using Bootstrap's online customization tool
2. Manually create your own color class, e.g. .btn-whatever
3. Use a LESS compiler and use the .button-variant mixin to create your own color class, e.g. .btn-whatever

2022 Update for Bootstrap 5

Bootstrap 5 has the same button-variant and button-outline-variant SASS mixins which can be used to customize the button color after bootstrap is imported...

/* import the Bootstrap */
@import "bootstrap";

/* ------- customize primary button color -------- */   
$mynewcolor:#77cccc;

.btn-primary {
    @include button-variant($mynewcolor, darken($mynewcolor, 7.5%), darken($mynewcolor, 10%), lighten($mynewcolor,5%), lighten($mynewcolor, 10%), darken($mynewcolor,30%));
}

.btn-outline-primary {
    @include button-outline-variant($mynewcolor, #222222, lighten($mynewcolor,5%), $mynewcolor);
}

https://codeply.com/p/UNvB5hRsfF

2019 Update for Bootstrap 4

Now that Bootstrap 4 uses SASS, you can easily change the primary button color using the button-variant mixins:

$mynewcolor:#77cccc;

.btn-primary {
    @include button-variant($mynewcolor, darken($mynewcolor, 7.5%), darken($mynewcolor, 10%), lighten($mynewcolor,5%), lighten($mynewcolor, 10%), darken($mynewcolor,30%));
}
    
.btn-outline-primary {
    @include button-outline-variant($mynewcolor, #222222, lighten($mynewcolor,5%), $mynewcolor);
}

https://codeply.com/p/JnV3xDDiaH (SASS demo)

This SASS compiles into the following CSS...

.btn-primary {
    color: #212529;
    background-color: #7cc;
    border-color: #5bc2c2
}

.btn-primary:hover {
    color: #212529;
    background-color: #52bebe;
    border-color: #8ad3d3
}

.btn-primary:focus,
.btn-primary.focus {
    box-shadow: 0 0 0 .2rem rgba(91, 194, 194, 0.5)
}

.btn-primary.disabled,
.btn-primary:disabled {
    color: #212529;
    background-color: #7cc;
    border-color: #5bc2c2
}

.btn-primary:not(:disabled):not(.disabled):active,
.btn-primary:not(:disabled):not(.disabled).active,
.show>.btn-primary.dropdown-toggle {
    color: #212529;
    background-color: #9cdada;
    border-color: #2e7c7c
}

.btn-primary:not(:disabled):not(.disabled):active:focus,
.btn-primary:not(:disabled):not(.disabled).active:focus,
.show>.btn-primary.dropdown-toggle:focus {
    box-shadow: 0 0 0 .2rem rgba(91, 194, 194, 0.5)
}

.btn-outline-primary {
    color: #7cc;
    background-color: transparent;
    background-image: none;
    border-color: #7cc
}

.btn-outline-primary:hover {
    color: #222;
    background-color: #8ad3d3;
    border-color: #7cc
}

.btn-outline-primary:focus,
.btn-outline-primary.focus {
    box-shadow: 0 0 0 .2rem rgba(119, 204, 204, 0.5)
}

.btn-outline-primary.disabled,
.btn-outline-primary:disabled {
    color: #7cc;
    background-color: transparent
}

.btn-outline-primary:not(:disabled):not(.disabled):active,
.btn-outline-primary:not(:disabled):not(.disabled).active,
.show>.btn-outline-primary.dropdown-toggle {
    color: #212529;
    background-color: #8ad3d3;
    border-color: #7cc
}

.btn-outline-primary:not(:disabled):not(.disabled):active:focus,
.btn-outline-primary:not(:disabled):not(.disabled).active:focus,
.show>.btn-outline-primary.dropdown-toggle:focus {
    box-shadow: 0 0 0 .2rem rgba(119, 204, 204, 0.5)
}

https://codeply.com/go/lD3tUE01lo (CSS demo)

To change the primary color for all classes see: Customizing Bootstrap CSS template and How to change the bootstrap primary color?

If you want to override any default properties in Bootstrap you have to make the properties as important.

.btn-primary, .btn-primary:hover, .btn-primary:active, .btn-primary:visited {
    background-color: #8064A2 !important;
}

I hope this works for you.

I guess you forgot .btn-primary:focus property and comma after .btn-primary

You also can use less and redefine some colors in variables.less file

With this in mind your code will be look like this:

.btn-primary,
.btn-primary:hover,
.btn-primary:active,
.btn-primary:visited,
.btn-primary:focus {
    background-color: #8064A2;
    border-color: #8064A2;
}