The text content background colour can be edited in this section of CSS:

.ds-advent-8 .et_pb_slide_description {
    float: right;
    width: 30% !important;
    text-align: center;
    padding: 30px !important;
    margin: 3% !important;
    background: rgba(255, 255, 255, .8);
}

The inactive slide dot navigation can be edited in this section of CSS:

.ds-advent-8 .et-pb-controllers a {
    background-color: transparent !important;
    border: 2px solid #fff;
    border-radius: 0;
    width: 10px;
    height: 10px;
    margin: 10px;
}

The active slide dot navigation colour can be edited within the module settings, it is set to white by default.