Change from outline to solid button colour in refresh theme

[EstherBui]

Hi Jess-FFF

You can try to follow this step
Step 1: Go to Edit code
Step 2: Find file base.css and add this code at the end of the file

button#quick-add-template--17779855589550__featured-collection-08645033590958-submit {
    background: rgba(var(--color-button-text));
    color: #fff;
}

Result:

Best,
Esther