Articulate Rise - Continue Button

That Custom style option just changes the background color of the block but not the button itself. If you want to change that button style you will have to reach for something like the Mighty Chrome extension or just append the CSS to your course after publishing. Lots of articles out there that talk about modifying your Rise course after the fact. That CSS is will want is something like this! 

.continue-btn {
    background-color: red;
}