Add variable to set blur for form :focus box shadows

[samwilliscreative]

I am trying to style my buttons and forms using v5, but running into issues with setting my focus styles. This is due to the way box shadow variables are built up;

$input-btn-focus-width:         .25rem !default;
$input-btn-focus-color-opacity: .25 !default;
$input-btn-focus-color:         rgba($component-active-bg, $input-btn-focus-color-opacity) !default;
$input-btn-focus-box-shadow:    0 0 0 $input-btn-focus-width $input-btn-focus-color !default;

As you can see, the blur value for the $input-btn-focus-box-shadow variable is explicitly set to 0. This is fine in this instance as I can manually re-declare this variable with my own prop;

$input-btn-focus-box-shadow:    0 0 $custom-blur $input-btn-focus-width $input-btn-focus-color;

However, there are issues when it comes to validation. The problem is that the .form-control class that includes the validation state selector mixin explicitly sets the box-shadow, meaning there is no way for me to overwrite the property using variables:

bootstrap\scss\mixins\_forms.scss line 60

&:focus {
    border-color: $color;
    box-shadow: 0 0 0 $input-focus-width rgba($color, $input-btn-focus-color-opacity);
}

I am therefore asking that a $input-btn-focus-blur variable be added so that the mixin can still work as intended, whilst giving users the ability to blur if they wish. Thanks.

[mdo]

For now, going to pass on this. Our goal is to keep focus styles consistent and obvious. Adding a blur makes them look like default box-shadows IMO.

[samwilliscreative]

For now, going to pass on this. Our goal is to keep focus styles consistent and obvious. Adding a blur makes them look like default box-shadows IMO.

Sure, that makes sense, but for those developers that need to customise Bootstrap, the additional variable would allow us to set a consistent value for the blur.

You could even initialise the variable with a value of 0 so as to keep the base Bootstrap styles that you mention.

[mdo]

Feel like opening a PR by chance? I wouldn't mind reviewing and thinking about it again.

[samwilliscreative]

@mdo I have opened a PR here: #33031