new file 100644
// List Groups
@mixin list-group-item-variant($state, $background, $color) {
.list-group-item-#{$state} {
color: $color;
background-color: $background;
// [converter] extracted a&, button& to a.list-group-item-#{$state}, button.list-group-item-#{$state}
}
a.list-group-item-#{$state},
button.list-group-item-#{$state} {
.list-group-item-heading {
color: inherit;
&:hover,
&:focus {
background-color: darken($background, 5%);
&.active,
&.active:hover,
&.active:focus {
color: #fff;
background-color: $color;
border-color: $color;