Squarewebsites Lazy Summaries Plugin: "Load More" button incorrect color

Site URL: https://www.designsite.com

Hi - we purchased the Squarewebsites Lazy Summaries plugin so we can display blog posts summary with a "Load More" button so visitors can keep clicking that button to view more. The section color button is set to black but the "Load More" button is displaying in gray. Does anyone know how to make the button black - maybe a little code? Thanks in advance - the URL is: https://www.designsite.com/

Add to Design > Custom CSS

/* Load more button */
.loadMoreButton {
    background-color: black;
    color: white;
}

Thank you so much tuanphan!