Fix for active reports read but not yet Resolved!
Thanks to @upnet
Add to extra.less.

Code:

.badgeContainer--visible:after
    {
        background-color: rgb(196, 194, 194);
        color: rgb(23, 23, 23);
    }

Quick fix for drop image color. Add to extra.less.

Code:

.fr-popup .fr-image-upload-layer {
    background-color: rgb(22, 22, 22);
}

I decided to create a zip with 2 files, adding the XF2.0 dark style and XF2.1 dark style. So those running XF2.0 are able to still use this style.

As you can see in the screenshot below, the XF2.1 file is for Xenforo version 2.1.