Hi,

For Product Bundles alert, please add the CSS code below to WP-Admin → Appearance → Customize → Additional CSS:

.woosb-alert {
    background-color: #222;
    color: #fff;
}

For Variations Radio Buttons, please add the CSS code below:

.woovr-variations.woovr-variations-default .woovr-variation.woovr-variation-active {
    background-color: #222;
    color: #fff;
}