Moves from 1.25em to 1em to better support custom font-size-base values. Most common would probably be .875rem (14px) and current sizing garbles that into 1.09-ish, thus causing the rendering issues in #31269.
Co-authored-by: Martijn Cuppens <martijn.cuppens@gmail.com>
$input-transition: border-color .15s ease-in-out, box-shadow .15s ease-in-out !default;
-$form-check-input-width: 1.25em !default;
+$form-check-input-width: 1em !default;
$form-check-min-height: $font-size-base * $line-height-base !default;
$form-check-padding-left: $form-check-input-width + .5em !default;
$form-check-margin-bottom: .125rem !default;