$custom-alert-color: firebrick;
$custom-second-color: yellowgreen;

@include button-ui(
    $color: darkgrey,
    $pressed-background-color: transparent,
    $pressed-color: blue,
    $pressed-icon-color: blue,
    $hovered-background-color: transparent,
    $pressed-hovered-background-color: transparent,
    $ui: 'addObject'
);

@include button-ui(
    $color: $custom-second-color,
    $icon-color: $custom-second-color,
    $pressed-background-color: $custom-second-color,
    $ui: 'addEntityButton'
);

@include button-ui(
    $color: $custom-alert-color,
    $icon-color: $custom-alert-color,
    $pressed-background-color: $custom-alert-color,
    $ui: 'removeEntityButton'
);